Tissue removal system with retention mechanism

ABSTRACT

Systems and methods for minimally invasive discectomy procedures are described herein. In some variations, a tissue removal system may comprise a handheld housing, an outer shaft comprising a distal portion and a proximal portion coupled to the handheld housing, a distal sheath coupled to the distal portion of the outer shaft, a motor, an inner shaft coupled to the motor, where the inner shaft is located partially within the outer shaft and partially within the distal sheath, a tip portion coupled to a distal portion of the inner shaft, and an elongate member distally extending through a distal opening of the inner shaft, the elongate member having a retracted configuration and an extended configuration, where the distal sheath comprises at least one element (e.g. at least one protrusion) that engages the tip portion to couple the tip portion to the distal sheath.

This application claims priority to U.S. Provisional Application Ser.No. 61/413,925, entitled “Tissue Removal System with RetentionMechanism,” filed Nov. 15, 2010, which application is incorporatedherein by reference in its entirety.

BACKGROUND

Vertebral disc herniation is a common disorder where a portion of avertebral disc, a cushion-like structure located between the vertebralbodies of the spine, bulges out or extrudes beyond the usual margins ofthe disc and the spine. Disc herniation is believed to be the result ofexcessive loading on the disc in combination with weakening of theannulus due to such factors as aging and genetics. Disc herniation andother degenerative disc diseases are also associated with spinalstenosis, a narrowing of the bony and ligamentous structures of thespine. Although disc herniation can occur anywhere along the perimeterof the disc, it occurs more frequently in the posterior andposterior-lateral regions of the disc, where the spinal cord and spinalnerve roots reside. Compression of these neural structures can lead topain, parasthesias, weakness, urine and fecal incontinence and otherneurological symptoms that can substantially impact basic dailyactivities and quality of life.

Temporary relief of the pain associated with disc herniation is oftensought through conservative therapy, which includes positional therapy(e.g. sitting or bending forward to reduce pressure on the spine),physical therapy, and drug therapy to reduce pain and inflammation. Whenconservative therapy fails to resolve a patient's symptoms, surgery maybe considered to treat the structural source of the symptoms. Surgicaltreatments for disc herniation traditionally involve open proceduresthat require extensive dissection of muscle, connective tissue and bonealong a patient's back as well as nerve manipulations to achieveadequate surgical exposure. These surgeries also expose the patient to asignificant risk of complications, due to the presence of criticalneurovascular structures near the surgical site as well as prolongedanesthesia. For example, a discectomy procedure may be used todecompress the herniation by accessing the affected disc and removing aportion of the disc and any loose disc fragments. To achieve sufficientaccess to the affected disc, a portion of the lamina or bony arch of thevertebrae may be removed, which increases the invasiveness of theprocedure and can destabilize the spine post -surgery. When discectomyfails to resolve a patient's symptoms, more drastic measures may includedisc replacement surgery or vertebral fusion.

Fractures of the vertebrae bodies are another common disorder of thespinal column. When a vertebra fractures, the usual shape of the bonebecomes compressed and distorted, which results in pain. These vertebralcompression fractures (VCF), which may involve the collapse of one ormore vertebrae in the spine, are a common finding and result ofosteoporosis. Osteoporosis is a disorder that often becomes more severewith age and results in a loss of normal bone density, mass andstrength. Osteoporosis often leads to a condition in which bones areincreasingly porous or full of small holes and vulnerable to breaking.In addition to osteoporosis, vertebrae can also become weakened bycancer or infection.

In some instances, fractures of the vertebral bodies may be treated withsurgical removal of the vertebral body and the implantation of avertebral body replacement device. Other treatments may includevertebroplasty and kyphoplasty, which are minimally invasive proceduresfor treating vertebral compression fractures (VCF). In vertebroplasty,physicians use image guidance to inject a cement mixture through ahollow needle into the fractured bone. In kyphoplasty, a balloon isfirst inserted through the needle into the fractured vertebral body torestore at least some of the height and shape of the vertebral body,followed by removal of the balloon cement injection into the cavityformed by the balloon.

BRIEF SUMMARY

In some variations, a tissue removal system may comprise a handheldhousing, an outer shaft comprising a distal portion and a proximalportion coupled to the handheld housing, a distal sheath coupled to thedistal portion of the outer shaft, a motor, an inner shaft coupled tothe motor, where the inner shaft is located partially within the outershaft and partially within the distal sheath, a tip portion coupled to adistal portion of the inner shaft, and an elongate member distallyextending through a distal opening of the inner shaft, the elongatemember having a retracted configuration and an extended configuration,where the distal sheath comprises at least one element that engages thetip portion to couple the tip portion to the distal sheath. In somevariations, the element may be a protrusion extending from an innersurface of the distal sheath. In certain variations, a plurality ofprotrusions (e.g., four protrusions) may extend from the inner surfaceof the distal sheath. The coupling between the tip portion and thedistal sheath may define at least one aspiration port (e.g. a pluralityof aspiration ports) therebetween. The distal sheath may comprise a wallportion having at least one aperture (e.g. a plurality of apertures,such as two apertures) therethrough. In some variations, the system maycomprise a stop member coupled to the tip portion. In certainvariations, the system may comprise a tissue transport assembly. Thetissue transport assembly may comprise the inner shaft and a helicalmember coupled to or integral with the inner shaft.

In some variations, a tissue removal system may comprise a handheldhousing, an outer shaft comprising a distal portion and a proximalportion coupled to the handheld housing, a distal sheath coupled to thedistal portion of the outer shaft, a motor, an inner shaft coupled tothe motor, where the inner shaft is located partially within the outershaft and partially within the distal sheath, a tip portion coupled to adistal portion of the inner shaft, and an elongate member distallyextending through a distal opening of the inner shaft, the elongatemember having a retracted configuration and an extended configuration,where the distal sheath comprises means for retaining the tip portion.

In certain variations, a tissue removal system may comprise a handheldhousing, an outer shaft comprising a distal portion and a proximalportion coupled to the handheld housing, a distal sheath coupled to thedistal portion of the outer shaft, a motor, an inner shaft coupled tothe motor, where the inner shaft is located partially within the outershaft and partially within the distal sheath, a tip portion coupled to adistal portion of the inner shaft, a stop member coupled to the tipportion, and an elongate member distally extending through a distalopening of the inner shaft, the elongate member having a retractedconfiguration and an extended configuration. The stop member maysurround an outer surface of the tip portion. In some variations, thestop member may be annular. In certain variations, the stop member maybe beveled. The system may further comprise a tissue transport assemblywhich may, for example, comprise the inner shaft and a helical membercoupled to or integral with the inner shaft.

In some variations, a tissue removal system may comprise a handheldhousing, an outer shaft comprising a distal portion and a proximalportion coupled to the handheld housing, a distal sheath coupled to thedistal portion of the outer shaft, a motor, an inner shaft coupled tothe motor, where the inner shaft is located partially within the outershaft and partially within the distal sheath, a tip portion coupled to adistal portion of the inner shaft, an elongate member distally extendingthrough a distal opening of the inner shaft, the elongate member havinga retracted configuration and an extended configuration, and means forlimiting proximal movement by the inner shaft.

Methods of accessing a target site in a patient are also described here.One variation of a method for accessing a target site in a patient maycomprise inserting a stylet (e.g. a straight stylet) into a cannula(e.g. a cannula comprising a non-linear configuration), inserting thestylet-cannula assembly into a patient (e.g. where the cannula is atleast partially straightened), and removing the stylet from the cannulawhile substantially maintaining the cannula in the patient. The methodmay additionally comprise inserting an instrument, such as a tissueremoval system, into the cannula.

Methods of accessing a target site in the spine region of a patient arealso described here. One variation of a method for accessing a targetsite in the spine region of a patient may comprise inserting a stylet(e.g. a straight stylet) into a cannula (e.g. a curved cannula with acurved distal portion) to form a first cannula-stylet assembly (e.g.with a straight distal portion). The first cannula-stylet assembly mayaccess the spine region, and the stylet may be proximally withdrawn fromthe first cannula-stylet assembly. A stylet (e.g. a curved stylet with acurved distal portion) may be inserted into the cannula to form a secondcannula-stylet assembly (e.g. with a curved distal portion). The secondcannula-stylet assembly may be advanced to the target site in the spineregion.

Methods for treating a herniated disc are also described here. Onevariation of a method for treating a herniated disc may compriseinserting a stylet (e.g. a straight stylet) into a cannula (e.g. acurved cannula with a curved distal portion) to form a firstcannula-stylet assembly (e.g. with a straight distal portion). The firstcannula-stylet assembly may penetrate the disc annulus of the herniateddisc. The stylet may be proximally withdrawn from the firstcannula-stylet assembly, and a stylet (e.g. a curved stylet with acurved distal portion) may be inserted into the cannula to form a secondcannula-stylet assembly (e.g. with a curved distal portion). The secondcannula-stylet assembly may be advanced to a herniated area. The styletmay be proximally withdrawn from the second cannula-stylet assembly, anda tissue removal device may be inserted into the cannula. A portion ofthe nucleus pulposus may be removed using the tissue removal device. Thetissue removal device may be proximally withdrawn from the cannula, anda stylet (e.g. a straight stylet) may be inserted into the cannula. Thestylet and the cannula may be proximally withdrawn.

Methods for treating a vertebral body are described here. One variationof a method for treating a vertebral body may comprise inserting astylet (e.g. a straight stylet) into a cannula (e.g. a curved cannula)to form a first cannula-stylet assembly (e.g. with a straight distalportion). The first cannula-stylet assembly may penetrate the surface ofthe vertebral body, and the stylet may be proximally withdrawn from thefirst cannula-stylet assembly. A stylet (e.g. a curved stylet with acurved distal portion) may be inserted into the cannula to form a secondcannula-stylet assembly (e.g. with a curved distal portion). The secondcannula-stylet assembly may be advanced into a target site within thevertebral body, and the stylet may be proximally withdrawn from thesecond cannula-stylet assembly. A tissue removal device may be insertedinto the cannula, and may remove a portion of cancellous bone. Thetissue removal device may be withdrawn proximally from the cannula. Astylet (e.g. a straight stylet) may be inserted into the cannula, andthe stylet and the cannula may be proximally withdrawn.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a portion of a lumbar spine.

FIG. 2 is a schematic side elevational view of a portion of the lumbarspine.

FIG. 3 is a schematic superior view of a portion of a lumbar vertebraand disc.

FIGS. 4A and 4B are schematic superior views of a herniated disc duringand after treatment, respectively.

FIG. 5A is a side elevational view of an embodiment of a tissue removaldevice; FIG. 5B is a detailed cutaway view of the device in FIG. 5A.

FIGS. 6A and 6B are side elevational views of an embodiment of tissueremoval device with a rotatable elongate member in its retracted andextended configurations, respectively.

FIG. 7 depicts another embodiment of a tissue removal device with arecessed groove.

FIG. 8 depicts another embodiment of a tissue removal device with amulti-filament elongate member.

FIG. 9 depicts another embodiment of a tissue removal device.

FIG. 10 depicts one embodiment of a tissue removal device with aplurality of rigid supports.

FIG. 11 depicts another embodiment of a tissue removal device with rigidsupports.

FIGS. 12A and 12B illustrate another embodiment of a tissue removaldevice with a helically-oriented elongate member in the retracted andextended states, respectively.

FIGS. 13A and 13B are side elevational and longitudinal cross-sectionalviews of another embodiment of a tissue removal device; FIG. 13C is aside elevational view of the tissue removal device of FIG. 13A with atissue-removing cable in an extended state.

FIGS. 14A and 14B are side elevational views of another embodiment oftissue removal device in the retracted and extended configurations,respectively.

FIG. 15 is an embodiment of a tissue removal device with tapered centralregion.

FIG. 16 is an embodiment of a tissue removal device with a narrowcorkscrew region.

FIG. 17 is a detailed view of one embodiment of an optional tissuetransport mechanism.

FIGS. 18A and 18B are perspective and side elevational views of anotherembodiment of a tissue removal device; FIG. 18C is a component view ofthe tissue removal device in FIGS. 18A and 18B; and FIG. 18D is across-sectional view of the tissue removal device in 18A and 18B with aportion of the housing removed.

FIG. 19A schematically depicts one embodiment of a flexible tissueremoval device; FIG. 19B is a schematic side elevational view of theproximal end of the flexible tissue removal device of FIG. 19A with aportion of the housing removed; FIG. 19C is a detailed view of thedistal end of the flexible tissue removal device of FIG. 19A in a bentconfiguration.

FIGS. 20A and 20B are schematic side and superior cross-sectional viewsof a steerable tissue removal device inserted into a vertebral disc,respectively.

FIG. 21A depicts the distal end of another embodiment of a tissueremoval device with a blunt tip and in an extended configuration; FIGS.21B to 21D depict various views of the tissue removal device in FIG. 21Ain the retracted configuration. FIG. 21E depicts one example of acutting mechanism that may be used with the tissue removal device inFIG. 21A.

FIG. 22 illustrates the tissue removal device of FIG. 21A with anoptional viewing chamber.

FIG. 23 illustrates an embodiment of a cannula and obturator deviceusable with various access systems.

FIGS. 24A to 24C depicts one embodiment of a method for performingvertebroplasty.

FIG. 25A schematically illustrates one embodiment of a straightcannula-stylet assembly comprising a straight cannula and a straightstylet; FIG. 25B to 25E depict various embodiments of the distal portionof the straight cannula-stylet assembly in FIG. 25A.

FIGS. 26A to 26D schematically illustrate one embodiment of a straightaccess to a target site for performing discectomy.

FIGS. 27A to 27E schematically illustrate various embodiments of aradiographic marker with a distal deployable wire.

FIGS. 28A to 28C schematically illustrate one embodiment of a straightaccess to a target site for performing vertebroplasty.

FIGS. 29A to 29C are schematic illustrations of the distal portion of acurved cannula-stylet assembly comprising a curved cannula and astraight stylet.

FIGS. 30A to 30C are schematic illustrations of the distal portion of acurved cannula-stylet assembly comprising a curved cannula and a curvedstylet.

FIGS. 31A to 31D schematically illustrate one embodiment of a curvedaccess to a target site for performing discectomy.

FIGS. 32A to 32C are schematic illustrations of the distal portion of acable-based tissue removal device inserted into a curved cannula.

FIGS. 33A to 33D schematically illustrate one embodiment of a curvedaccess to a target site for performing vertebroplasty.

FIG. 34A depicts one variation of a stylet that may be used with acurved cannula illustrated in FIG. 34B and/or a straight cannulaillustrated in FIG. 34C.

FIGS. 35A and 35B depict another variation of a tissue removal devicethat may be used in a discectomy procedure.

FIG. 36A depicts a partial cutaway view of the handle of a tissueremoval device. FIGS. 36B to 36E illustrate one example of a mechanismthat enables a cable of a tissue removal assembly to be rotated by amotor and simultaneously axially translated by a slider.

FIG. 37 illustrates a perspective view of the tissue removal device fromFIG. 35A.

FIGS. 38A to 38G illustrate one variation of a travel limiter that maybe used with a tissue removal device. FIGS. 38B and 38C depict how aportion of the travel limiter may be assembled together. FIG. 38D to 38Gdepict a latch mechanism that may be used with the travel limiter.

FIGS. 39A to 39G illustrate different configurations and variations oftissue removal assemblies that may be used with the tissue removaldevices described herein. FIGS. 39D to 39F schematically illustrateexamples of cable configurations that may be used with the tissueremoval assembly depicted in FIG. 39A.

FIGS. 40A to 40F illustrate another variation of a tissue removalassembly.

FIGS. 41A to 41H depict examples of a tissue transport assembly that maybe used to transport tissue between the tissue removal assembly and acollector of the tissue removal device. FIG. 41A depicts one variationof a drive member. FIGS. 41B to 41H depict variations of impellers thatmay be used with the drive member of FIG. 41A.

FIGS. 42A and 42B are side and rear elevational views of a variation ofa tissue removal system; FIG. 42C is a cutaway view of the tissueremoval system in FIG. 42A with a portion of the handle housing removed.

FIG. 43A is a side elevational view of a variation of a tissue removalsystem; FIG. 43B is an enlarged view of region 43B in FIG. 43A; FIG. 43Cis an enlarged view of a portion of the system of FIG. 43A; FIG. 43D isa cross-sectional view of a portion of a tissue removal assembly of thesystem of FIG. 43A; FIGS. 43E and 43F depict coupled distal sheath andtip components of the system of FIG. 43A; FIG. 43G is a perspective viewof a distal sheath component of the system of FIG. 43A; FIGS. 43H to 43Jare side, front and rear elevational views, respectively, of the distalsheath component of the system of FIG. 43A; FIGS. 43K and 43L illustratecoupled distal sheath, tip, and stop member components of the system ofFIG. 43A; FIG. 43M is a side perspective view of the stop membercomponent of the system of FIG. 43A; FIGS. 43N, 43O and 43P are front,rear and side elevational views, respectively, of the stop membercomponent of the system of FIG. 43A; FIG. 43Q is a side elevational viewof the tip component of the system of FIG. 43A; FIG. 43R is anillustrative side view of the tip component of the system of FIG. 43A;FIGS. 43S and 43T are perspective and side elevational views,respectively, of an alternative tissue removal assembly including analternative stop member component; FIG. 43U is an side elevational viewof a distal portion of the alternative tissue removal assembly of FIGS.43S and 43T.

DETAILED DESCRIPTION

FIGS. 1 and 2 are schematic views of a lumbar region of a spine 100. Thevertebral canal 102 is formed by a plurality of vertebrae 104, 106, and108, which comprise vertebral bodies 110, 112 and 114 anteriorly andvertebral arches 116 and 118 posteriorly. The vertebral arch andadjacent connective tissue of the superior vertebra 104 has been omittedin FIG. 1 to better illustrate the spinal cord 122 within the vertebralcanal 102. Spinal nerves 124 (FIG. 2) branch from the spinal cord 122bilaterally and exit the vertebral canal 102 through intervertebralforamina 126 (seen best in FIGS. 2 and 3) that are formed by theadjacent vertebra 104, 106 and 108. The intervertebral foramina 126 aretypically bordered by the inferior surface of the pedicles 120, aportion of the vertebral bodies 104, 106 and 108, the inferior articularprocesses 128, and the superior articular processes 130 of the adjacentvertebrae. Also projecting from the vertebral arches 116 and 118 are thetransverse processes 132 and the posterior spinous processes 134 of thevertebrae 106 and 108. Located between the vertebral bodies 110, 112 and114 are the vertebral discs 123.

Referring to FIG. 3, the spinal cord 122 is covered by a thecal sac 136.The space between the thecal sac 136 and the borders of the vertebralcanal 102 is known as the epidural space 138. The epidural space 138 isbound anteriorly and posteriorly by the longitudinal ligament 140 andthe ligamentum flavum 142 of the vertebral canal 102, respectively, andlaterally by the pedicles 120 of the vertebral arches 116 and 118 andthe intervertebral foramina 126. The epidural space 138 is contiguouswith the paravertebral space 144 via the intervertebral foramina 126.

Referring to FIG. 4A, a vertebral disc 150 typically comprises an outer,multi-layer, annular band of connective tissue, known as the annulusfibrosus 152, which encases a gel-like resilient material known as thenucleus pulposus 154. The nucleus pulposus 154 acts as a shock-absorbingstructure for the forces acting on the spine. Both the annulus fibrosus152 and the nucleus pulposus 154 are elastic collagenous structureswhich, over time, may decrease in elasticity and cause the nucleuspulposus to bulge out at a weakened region of the annulus fibrosus 152,and even extrude through the annulus fibrosus 152. FIG. 4A schematicallydepicts an extrusion 156 of the nucleus pulposus 154, which haspenetrated through the wall of the annulus fibrosus 152 within anintervertebral foramen 126 and compressed a nerve 124 exiting the spine.Although the extrusion 156 remains in continuity with the remainingnucleus pulposus 154, the extrusion 156 may sometimes pinch off orseparate, resulting in the sequestration of a portion of the nucleus.

As mentioned previously, treatments of disc herniation may involveinternal access to the affected disc with removal or volume reduction ofthe disc material. This may relieve the pressure causing the bulging orextrusion to at least partially restore the profile of the disc. In FIG.4A, for example, a tissue removal device 200 has been inserted into theextrusion 156 extending out of the herniated disc 150. The tissueremoval device 200 is then actuated to break up and remove the extrudedmaterial. In some embodiments, the tissue removal device 200 may befurther inserted distally into the disc 150. Additional tissue withinthe disc 150 may then be removed. As shown in FIG. 4B, after removing avolume of the nucleus pulposus 154 and relieving some of the pressurecausing the extrusion 156, the extrusion 156 was able to retract backinto the disc 150, thereby reducing the extrusion pathway 160 andrelieving compression of the spinal nerve 124. Although contralateralaccess of the herniated disc is depicted in FIG. 4A, ipsilateral accessmay also be used. Furthermore, direct tissue removal of the extrudedherniated disc may also be performed.

Devices used to remove disc tissue for discectomy or nucleotomy mayinclude lasers, discectomes, trephines, burrs, rongeurs, rasps, curettesand cutting forceps. Many of these devices have a substantialcross-sectional size, and when inserted into a disc, create an insertionchannel which substantially compromises the integrity of the annulusfibrosus at the insertion site. Thus, any remaining nucleus pulposusmaterial may extrude or herniate through the insertion site withouttaking measures to suture or otherwise close the insertion site, therebyadding complexity to the discectomy or nucleotomy procedure.

In contrast, a tissue removal device may be configured for minimallyinvasive insertion toward or into a vertebral disc without requiringsuturing, gluing or other procedures to seal or close the access pathwayinto the disc. The tissue removal device may be used for any of avariety of procedures, including but not limited to discectomy,nucleotomy, lysis of adhesions, and other tissue removal procedures inthe spine and throughout other regions of the body. FIG. 5A depicts oneembodiment of a tissue removal device 2, comprising an outer tube 4coupled to a housing 6. The static outer tube 4 covers a rotating driveshaft (not shown) that is attached to a tissue removal assembly 8. Inother embodiments, the tissue removal device 2 (and other tissue removaldevices described herein, as appropriate) may lack an outer tube and thedrive shaft of the tissue removal device may be inserted into a lumen ofa cannula or other access device. The housing 6 contains one or morecomponents configured to control the tissue removal assembly 8 and otheroptional features of the tissue removal device 2. The tissue removalassembly 8, examples of which are described in greater detail below, maybe configured to cut, chop, grind, burr, pulverize, debride, debulk,emulsify, disrupt or otherwise remove tissue when rotated at variousspeeds. Emulsification includes, for example, forming a suspension oftissue particles in a medium, which may be the existing liquid at thetarget site, liquid added through the tissue removal device, and/orliquid generated by the debulking of the tissue. Optional components oftissue removal device 2 and other tissue removal devices describedherein may include, but are not limited to, a motor configured to rotateor move the tissue removal assembly, a power source or power interface,a motor controller, a tissue transport assembly, an energy delivery orcryotherapy assembly, a therapeutic agent delivery assembly, a lightsource, and one or more fluid seals. The optional tissue transportassembly may comprise a suction assembly and/or a mechanical aspirationassembly. One or more of these components may act through the outer tube4 to manipulate the tissue removal assembly and/or other componentslocated distal to the housing 6, or from the housing 6 directly. Forexample, the tissue removal device 2 further comprises an optional port20 that may be attached to an aspiration or suction source to facilitatetransport of tissue or fluid out of the target site or patient. Thesuction source may be a powered vacuum pump, a wall suction outlet, or asyringe, for example.

The housing 6 may further comprise a control interface 10 that may beused to control the power state of the tissue removal device 2,including but not limited to on and off states. In this particularembodiment, the control interface 10 comprises a lever or pivot member,but in other embodiments, control interface 10 may comprise a pushbutton, a slide, a dial or knob. In some embodiments, the controlinterface 10 may also change the motor speed and/or movement directionof the tissue removal assembly 8. A bi-directional tissue removal devicemay be provided, for example, as a potential safety feature should thetissue removal assembly 8 get lodged in a body tissue or structure. Theweb-like connective tissue that may be found in the epidural space mayget wound onto or caught up on the burr device or other tissue removaldevice. This connective tissue may be dislodged with a bi-directionaltissue removal device by reversing the direction of rotation to unwindthe tissue. The control interface 10 may be analog or digital, and maycomprise one or more detent positions to facilitate selection of one ormore pre-selected settings. In other embodiments, a separate motorcontrol interface may be provided for one or more features of the motor.In still other embodiments, control interfaces for other features of thetissue removal device may be provided.

Referring to FIGS. 6A and 6B, the tissue removal assembly 200 maycomprise at least one elongate member 202 having a proximal section 204and distal section 206, with each section coupled to a rotatable shaft208. The elongate member 202 has a retracted configuration, shown inFIG. 5A, and an extended configuration, shown in FIG. 5B. In theextended configuration, at least a portion 210 of the elongate member202 is displaced farther away from the rotatable shaft 208 than the sameportion 210 in the retracted configuration. To adjust the configurationof the elongate member 202, the proximal section 204 of the elongatemember 202 may be slid in or out of a proximal opening 212 of therotatable shaft 208 to alter the exposed length of the elongate member208 between the proximal opening 212 and a distal opening 214 (or distalattachment of the distal section 206) of the elongate member 202. Thepercentage change in the length of the elongate member 202 from itsretracted configuration to its extended configuration may be in therange of about 10% to about 60% or more, sometimes about 20% to about40%, and other times about 15% to about 20%. In some embodiments,transformation of the elongate member 202 between configurations mayinclude sliding its distal section 206 in or out of the distal opening214, in addition to or in lieu of movement between the proximal section204 and the proximal opening 212.

The tissue removal device 200 may further comprise a distal head 216with a conical configuration, as depicted in FIGS. 6A and 6B. Other headconfigurations are also contemplated, including but not limited to anovoid configuration, a dome configuration, a concave configuration, acube configuration, etc. The head 216 may be configured to penetrate ordissect body tissue, such as the annular wall of a vertebral disc, andmay be used while the rotatable shaft 208 is being rotated, or when therotatable shaft 208 is not rotated. In other embodiments, the head maycomprise multiple points or edges that may be used to cut, chop, grind,burr, pulverize, debride, debulk, emulsify, disrupt or otherwise removetissue or body structures. In still other embodiments, the head maycomprise surfaces with a grit that may be used as a burr mechanism. Thegrit number may range from about 60 to about 1200 or more, sometimesabout 100 to about 600, and other times about 200 to about 500.

The head may optionally comprise a port or aperture which may be used toperform suction or aspiration at the target site and/or to perfusesaline or other biocompatible fluids or materials to the target site.Use of saline or other cooling materials or liquids, for example, may beused to limit any thermal effect that may occur from frictional or otherforces applied to the target site during removal procedures. The salineor other materials may or may not be chilled. In other embodiments, oneor more therapeutic agents may be provided in the saline or fluid forany of a variety of therapeutic effects. These effects may includeanti-inflammatory effects, anti-infective effects, anti-neoplasticeffects, anti-proliferative effects, hemostatic effects, etc.

In some embodiments, the rotatable shaft may optionally comprise one ormore recesses or grooves on its outer surface to receive the elongatemember 202. For example, FIG. 7 depicts a single groove 218 between theproximal and distal openings 212 and 214 of the rotatable shaft 208. Thedepth and cross-sectional shape of the groove 218 may be configured topartially or fully receive the elongate member 202.

The elongate member 202 may comprise any of a variety of materials andstructures. For example, the elongate member 202 may comprise titanium,a nickel-titanium alloy, stainless steel, a cobalt-chromium alloy, apolymer (e.g. nylon, polyester and polypropylene) or a combinationthereof. The elongate member 202 may also have a monofilament ormulti-filament structure. FIG. 8, for example depicts a tissue removaldevice 300 with an elongate member comprising a multi-filament cable302. In some embodiments, a multi-filament elongate member may providegreater flexibility and/or stress tolerance than a monofilament elongatemember. A multi-filament elongate member may comprise any number offilaments, from about 2 filaments to about 50 filaments or more,sometimes about 3 filaments to about 10 filaments, and other times about5 filaments to about 7 filaments. In some embodiments, the elongatemember has a flexural modulus that is less than the flexural modulus ofbony tissue, such as the endplates of the vertebral bodies adjacent to avertebral disc. In some instances, by providing a flexural modulus thatis lower than certain body structures, damage to those body structuresmay be reduced or substantially eliminated. Thus, in some discectomy ornucleotomy procedures, a tissue removal device with an elongate memberthat has a flexural modulus that is less than the flexural modulus ofboth the bony tissue of the vertebral endplates and the flexural modulusof the annular fibrosus walls of the disc may be able to pulverize theinner tissue of a disc without damaging the adjacent walls of the discor the vertebral bone. In some examples, the flexural modulus of theelongate member may be less than about half of the flexural modulus ofintact bone or the annular fibrosis tissue, while in other embodiments,the flexural modulus of the elongate member is at least about 5 timeslower, or even at least about 10 times or 20 times lower. In someembodiments, the flexural modulus of the elongate member is generallyuniform along its exposed length or between its coupling sites on therotatable shaft. For example, in some embodiments, the flexural modulusmay not vary by more than about a 10× range along the length of theelongate member, while in other embodiments, the variation may be nogreater than a range of about 5× or about 2×.

In some variations, the elongate member (e.g., multifilament ormonofilament) of any of the variations described herein may be coated orsheathed with one or more materials. For example, the elongate membermay be coated with polyimide, parylene, silicone, or urethane, or otherpolymer, or with an adhesive. The material may or may not penetrate intoor between the filaments of a multi-filament elongate member. Thecoating may be applied by spray coating or dip coating, or other coatingmethod, for example. In other examples, the material may be providedbetween the filaments but not on the exposed outer surfaces of thefilaments, e.g. the material may be at least partially wiped or removedby air blowing from the outer surface of elongate member after sprayingor dipping. In other variations, the coating material may comprise asheath or tube that is glued or heat shrunk to the elongate member 202.In some variations, the sleeve or coating has an average thickness inthe range of about 0.001 to about 0.01 inches, about 0.002 to about0.008 inches, or about 0.003 to about 0.005 inches. The coating, sheathor tube may further comprise one or more support structures, such as ahelical L304 stainless steel wire that is partially or completelyembedded into the coating, sheath or tube, or adhered to the innerand/or outer surface of the coating, sheath or tube. The coating orsleeve may or may not cover the entire length of exposed or exposableelongate member or cable, and may also cover the unexposed portions ofthe elongate member or cable. In some variations, the coating or sleevemay cover a portion of the proximal, middle, or distal portion of theelongate member and may be characterized as a percentage of coveragerelative to the overall exposed or exposable length of the elongatemember or cable, e.g. about 10%, about 20%, about 30%, about 40%, about50%, about 60%, about 70%, about 80%, about 90%, or about 100%.

Although the elongate member 202 may have a retracted configuration andan extended configuration, the elongate member 202 may also have anative or base configuration in which the stress acting on the elongatemember 202 is reduced compared to other configurations. This nativeconfiguration, if any, may be the retracted configuration, the extendedconfiguration, or a configuration between the retracted configurationand the extended configuration. Thus, the stress exerted on the elongatemember 202 in the native configuration may be lower in either theretracted configuration or the extended configuration, or a thirdconfiguration that is different from the retracted configuration or theextended configuration. In some embodiments, a native configuration thatis similar to the extended configuration may be beneficial because alower baseline stress acting on the elongate member 202 while in itsextended configuration may provide greater stress tolerance fromimpacting tissues or bone before stressing the elongate member 202beyond its fracture point. Although adjusting the elongate member 202 toits retracted configuration may result in greater stress acting on theelongate member 202, the stress may occur only during insertion andremoval of tissue removal device 200, and without the impact stressesthat act on the elongate member 202 during use. To produce the elongatemember 202 with a particular native configuration, the manufacturingsteps may vary depending upon the particular material or compositionused. In embodiments where the elongate member 202 comprises stainlesssteel (e.g. 304L or 316L stainless steel) or nickel-titanium alloys, forexample, a series of deformation steps and heat annealing steps may beused to form the elongate member 202 in a native, expandedconfiguration.

The elongate member 202 may have any of a variety of cross-sectionalshapes, including but not limited to square, rectangular, trapezoidal,circular, elliptical, polygonal, and triangular shapes, for example. Thecross-sectional shape and/or size may be uniform along its length, ormay vary along one or more sections. In one example, the elongate membermay have a tapered configuration, with a cross-sectional area thatdecreases from its proximal section to its distal section, or from itsdistal section to its proximal section. In some embodiments, theelongate member 202 may comprise a metallic wire or other elongatestructure with a diameter or maximum cross-sectional dimension in therange of about 0.2 mm to about 1.5 mm or more, sometimes about 0.3 mm toabout 1 mm, and other times about 0.3 mm to about 0.5 mm.

In some embodiments, the elongate member may be micropolished.Micropolishing may or may not reduce the risk of chipping or fragmentformation when used to debride harder or denser body structures ortissues. In other embodiments, the elongate member may comprise a gritsurface or a cutting edge along one or more portions of its length. Forexample, the elongate member may comprise a cutting edge with an edgeangle in the range of about 90 degrees to about 10 degrees, sometimesabout 75 degrees to about 15 degrees, and other times about 60 degreesto about 30 degrees, and still other times about 45 degrees to about 40degrees. The configuration of the elongate member surface may be thesame or different on opposing sides of the elongate member. For example,having different configuration on the leading surface compared to thetrailing surface of the elongate member, may permit changes in thecutting, chopping, debriding, or emulsifying characteristics of theelongate member 202, depending upon its direction of rotation. In otherembodiments, the leading and trailing surfaces may generally have thesame features and may have similar performance in either rotationdirection, but may also permit users to switch from one surface to theother if one surface has worn out. In still other embodiments, therotation direction may be user-selected, depending upon the relativelocation of the tissue to be removed and any critical anatomicalstructures. For example, the rotation direction may be selected suchthat if the cutting edge catches on the tissue or structure, the tissuedisrupting element will be rotated away from the critical anatomicalstructure(s), if any.

As depicted in FIG. 6B, the elongate members 202 may have proximal anddistal sections 204 and 206 with generally similar lengths and generallystraight configurations, and a curved or angled middle portion 210between them. FIG. 9, however, depicts another embodiment of a tissueremoval device 310, comprising an elongate member 312 with proximal anddistal sections 314 and 316 with concave configurations and a middlesection 318 with a convex configuration. Other configurations are alsocontemplated, comprising any of a variety of linear, curved, or angledsections, and comprising symmetrical or asymmetrical configurations. Inthe embodiment depicted in FIG. 9, the longitudinal distance 320 betweenthe proximal and distal openings 322 and 324 of the rotatable shaft 326may be in the range of about 4 mm to about 30 mm or more, sometimesabout 6 mm to about 15 mm, and other times about 9 mm to about 12 mm.The longitudinal distances 328 and 330 from the proximal and distalopenings 322 and 324 to the peak displacement distance 332 of theelongate member 302, respectively, may be similar or different. In someembodiments, the distances 328 and 330 may be in the range of about 2 mmto about 20 mm or more, sometimes about 3 mm to about 10 mm, and othertimes about 4 mm to about 6 mm. The peak displacement distance 332between the middle section 318 and the rotatable shaft 326 can vary,depending upon the particular configuration of the elongate member. Theminimum displacement distance (not shown) of the middle section need notbe zero, as in embodiments where the elongate member does not fullyretract along its entire length against the rotatable shaft. In someembodiments, the displacement distance 318 may be in the range of about2 mm to about 10 mm or more, sometimes about 3 mm to about 8 mm, andother times about 4 mm to about 6 mm. In some embodiments, the peakdisplacement distance 322 may be characterized relative to thelongitudinal distance 320 or the proximal or distal distances 328 and330 to the peak distance. For example, the ratio of the peakdisplacement distance to the longitudinal distance may be in the rangeof about 0.2 to about 1 or more, sometimes about 0.3 to about 0.8, andother times about 0.4 to about 0.5. The distance 334 between the distalopening 324 of the rotatable shaft and the distal head 336 may be in therange of about 0.5 mm to about 5 mm or more, sometimes about 1 mm toabout 4 mm, and other times about 2 mm to about 3 mm. The length 338 ofthe head 336 may be in the range of about 2 mm to about 15 mm or more,sometimes about 3 mm to about 10 mm, and other times about 4 mm to about5 mm. In embodiments comprising a conical or tapered head, the angle 340of the head configuration may be in the range of about 10 degrees toabout 90 degrees or more, sometimes about 20 degrees to about 60degrees, and other times about 30 degrees to about 45 degrees.

The diameter 342 (or maximum transverse axial dimension) of therotatable shaft 326 and/or head 336 may be in the range of about 0.5 mmto about 5 mm or more, sometimes about 1 mm to about 3 mm, and othertimes about 1 mm to about 2 mm. The diameter of the shaft 326 and thehead 336 may be similar or different. The maximum cross-sectionaldimension of the proximal and distal openings may be the same ordifferent, and may be in the range of about 0.1 mm to about 1.5 mm ormore, sometimes about 0.2 mm to about 1 mm, and other times about 0.4 mmto about 0.8 mm.

The width of the groove 344 of the rotatable shaft 326, if any, may bein the range of about 0.2 mm to about 1.5 mm or more, sometimes about0.3 mm to about 1 mm, and other times about 0.4 mm to about 0.7 mm. Thewidth of the groove 344 may also be characterized as a percentage of thediameter or width of the elongate member, which may be in the range ofabout 80% to about 400% or more, sometimes about 105% to about 300%, andother times about 150% to about 200%. As mentioned previously the depthof the groove 344 may be less than, similar to, or greater than themaximum transverse dimension of the elongate member 312. In someembodiments, the groove depth or average groove depth may be in therange of about 0.2 mm to about 2 mm or more, sometimes about 0.4 mm toabout 1 mm, and other times about 0.6 mm to about 0.8 mm. In otherembodiments, the depth of the groove may be a percentage of the depth ofthe elongate member, in the range of about 20% to about 200% or more,sometimes about 50% to about 125%, and other times about 40% to about100%.

Although a single elongate member 202 is provided in the tissue removaldevice 200 depicted in FIG. 6A, other embodiments may comprise two ormore elongate members. In some embodiments, however, a single elongatemember may permit higher rotational speeds, due the reduced surface dragcompared to tissue removal devices with multiple elongate members. Inembodiments with multiple elongate members, the elongate members may bedistributed uniformly or non-uniformly around the perimeter of therotatable shaft. In some embodiments, each elongate member may have itsown proximal and distal openings, but in other embodiments, two or moreelongate members may share a proximal and/or distal opening. Theproximal and/or distal openings may be located at the same or differentlongitudinal position on the rotatable shaft, and each elongate membermay have the same or different length or configuration. The elongatemembers may be independently adjustable or adjustable in groups.

Referring to FIG. 10, in some embodiments, the elongate member 350 ofthe tissue removal device 352 may comprise other structures 354, 356 and358 attached or coupled to the flexible elongate member 350. Thesestructures may comprise any of a variety of structures, including tubes,rods, bars, cutting discs or other cutting members, beads or otherstructures. In the specific example depicted in FIG. 10, the elongatemember 352 comprises rigid sections 354, 356 and 358 alternating betweenflexible segments 360, 362, 364 and 366. One or more flexible segmentsmay also be substituted with a mechanical joint, such as a pin joint ora hinge joint. In some embodiments, the flexible elongate segments 360,362, 364 and 366 are part of a single contiguous flexible elongatemember that passes through a lumen of each rigid section 354, 356 and358 or are otherwise coupled to each rigid section 354, 356 and 358. Inother embodiments, one or more of the flexible segments 360, 362, 364and 366 are separate and interconnect only two rigid sections 354, 356and 358 or a rigid section and the rotatable shaft 368 or a structuretherein. The particular number, shape, flexibility/rigidity, lengths andlocations of the rigid segments and flexible segments may vary and neednot be uniform or symmetrical. In some embodiments, the percentage ofrigid section to flexible section along the length of the fully extendedelongate member may in the range of about 0 to about 99%, sometimesabout 50% to about 95%, and other times about 75 to about 90%. In someembodiments, the length of the flexible segment may be less than about75% of the length of the adjacent rigid segments, sometimes less thanabout 50%, and other times less than about 20% or about 10%.

In the example shown in FIG. 10, the tissue removal device 352 comprisesone rigid section 354 that is larger than the other rigid sections 356and 358. The section located at the peak displacement distance of theelongate member 350 may be a flexible segment 362 as shown in FIG. 10,or a rigid section in other embodiments. The rigid sections 354, 356 and358 are generally linear in shape, but may also be curved or angled orany combinations thereof. The elongate member 350 in FIG. 10 is alsogenerally configured to lie in a single plane in both the retracted andextended configurations, but in other embodiments, one or more rigid orflexible sections may be oriented out of plane in the retracted and/orextended configurations. As further illustrated in FIG. 10, the shaft368 may comprise a groove 369, or a region of the shaft with a narrowdiameter or axial transverse dimension, which may reduce the overallcross-sectional area of the tissue removal device 352 by permitting theelongate member 352 to protrude less when in the retractedconfiguration.

As shown in FIG. 10, the elongate member 350 in the extended state mayhave flexible sections 366 and 360 located about its proximal and distalopenings 370 and 372. In other embodiments, however, the elongate membermay have a rigid section or other structure about the proximal or distalopenings in the extended state. In FIG. 11, for example, the tissueremoval device 380 comprises a generally symmetrical elongate member 382with proximal and distal rigid members 384 and 386 interconnected by aflexible cable 388. In the extended configuration, the rigid members 384and 386 are partially located or recessed within the proximal and distalopenings 390 and 392 of the rotatable shaft 394. In some furtherembodiments, having rigid members 384 and 386 at the proximal and distalopenings 390 and 392 may reduce the tilting or bending of the elongatemember 382 with respect to the shaft 394. The degree with which theelongate member 382 is restricted may depend, for example, on the widthsof the openings 390 and 392 and the rigid member 384 and 386, thelengths 396 and 398 of the rigid member 384 and 386 outside and insidethe shaft 394, the lengths 400 of the flexible segment(s), and theoverall diameter of the shaft 394, and the degree of rigidity of therigid members 384 and 386. As further shown in FIG. 11, the shaft 394may further comprise a groove 400 or other configuration with a reduceddiameter or transverse axial dimension. At least a portion of the groove400 or configuration is located between the proximal and distal openings390 and 392, but the groove 400 or configuration may also be locatedproximal or distal to the openings 390 and 392, respectively.

As shown in FIGS. 12A and 12B, in some embodiments, the tissue removaldevice 420 may have proximal and distal openings 422 and 424 which arelocated at different circumferential locations along the longitudinallength of the rotatable shaft 426, and/or where the elongate member 428comprises at least one section having a helical, twisted or skewedconfiguration with respect to the rotatable shaft 426. FIG. 12A depictsthe tissue removal device 420 in a retracted or collapsed configuration,while FIG. 12B depicts the tissue removal device 400 in an extended orexpanded configuration. By extending the elongate member 408 through theproximal opening 422 of the shaft 426, the elongate member 426 maybecome axially compressed and expand radially outward from the shaft426.

The configuration of the elongate member may vary in the direction ofturning. For example, the elongate member may have a right orleft-handed spiral orientation (i.e. a clockwise or counter-clockwiseorientation). In FIGS. 12A and 12B, for example, the elongate member 428has a left-handed or counter-clockwise spiral orientation (as viewedfrom the proximal end of the tissue removal device 420). The spiralorientation of the elongate member 428 may be the same as the rotationdirection of the shaft 426, or be the opposite of the rotationdirection. The spiral configuration of the elongate member 428 may becharacterized in any of a variety of ways. For example, the absolutenumber of turns in the elongate member may be anywhere in the range fromabout zero (e.g. a linear elongate member) to about 4 turns or more,sometimes about a ¼ turn to about 1½ turns, and other times about ½ turnto about one turn. In other embodiments, the spiral configuration may becharacterized by its rate of turning, which may be calculated orrepresented as the number of turns per millimeter or centimeter along alength of the elongate member. In some embodiments, the rate of turningmay be in the range of about 0.3 turns/cm to about 2 turns/cm or more,sometimes about 0.7 turn/cm to about 1.5 turns/cm, and other times about0.9 turns/cm to about 1 turn/cm. The elongate member 428 may also becharacterized by its pitch angle, which may be in the range of about 0degrees to about 90 degrees, sometimes about 5 degrees to about 90degrees, and other times about 45 degrees to about 85 degrees. Thespiral configuration of the elongate member may be generally curvedalong its length, but may also comprise multiple linear segments withangled or curved bends in between. The configuration of the spiralelongate member in the retracted and extended configuration may vary,depending upon the flexibility of the elongate member, the manner andangle with which one or more ends of the elongate member are attached orfixed to the rotatable shaft, and the native configuration of theelongate member.

As shown in FIGS. 13A to 13C, a tissue removal device 450 with a spiralelongate member 452 may also comprise one or more grooves 454 on therotatable shaft 456. The groove 454 may facilitate seating and/orsecuring of the elongate member 452 in its retracted configuration. Ascan be seen in FIG. 13C, the spiral configuration of the elongate member452 and the groove 454 may not be uniform along the length of therotatable shaft 456. The distal groove 458 adjacent to the distalopening 460 comprises approximately a ½ turn along a longitudinaldistance that is about 50% shorter than the ½ turn of the middle groove462, while the proximal groove 464 between the middle groove 462 and theproximal opening 466 is generally linear. In some embodiments, thechange in turn rate may be in the range of about zero to about 4turns/cm or more, other times about zero to about 1 turn/cm, and othertimes about zero to about 0.5 turns/cm. In the particular embodimentdepicted in FIGS. 13A to 13C, the distal portion 468 of the elongatemember 452 remains generally wrapped around the shaft 456 in the distalgroove 458 in the extended configuration, while the proximal portion 470of the elongate member 452 bows radially outward. As can be seen in FIG.13C, in this particular configuration, the peak displacement distance472 of the elongate member 452 is located closer to the proximal opening466 of the shaft 456 than the distal opening 460. The proximal anddistal openings 466 and 460 may be oriented perpendicular to the outersurface of the shaft 456, or may be oriented at an angle or tangent withrespect to the outer surface of the shaft 456, which may reduce stressesexerted onto the elongate member 452 at the openings 460 and 466. Theedges of the groove 454 may also rounded along its length or at leastabout the openings 460 and 466. The elongate member, however, may beconfigured with a peak displacement distance located anywhere betweenthe proximal and distal openings, or even extending distal to the distalopening and/or proximal to the proximal opening. In other embodiments,the elongate member may even comprise multiple peak displacementdistances (e.g. a multi-angle, undulating or sinusoidal elongate memberin the extended configuration). In some embodiments, the peakdisplacement distance 472 is in the range of about 0.5 to about 10 timesgreater than the diameter or transverse axial dimension of the shaft456, sometimes about 1 to about 5 times greater, and other times about 2times to about 3 times greater. The longitudinal location of the peakdistance may be characterized as a relative position from the proximalto distal openings, which may be about −20% or less, about −10%, about0%, +10%, about +20%, about +30%, about +40%, about +50%, about +60%,about +70%, about +80%, about +90%, about +100%, about +110% or about+120% or more.

Referring now to FIGS. 14A and 14B, in some embodiments, the tissueremoval device 480 may comprise a shaft 482 with a narrowed region 484.At least a portion of the narrowed portion 484 may be located betweenthe proximal and distal attachments or openings 486 and 488 from whichthe elongate member 490 protrude, but in other embodiments, at least aportion of the narrowed portion 484 may be proximal or distal to theopenings 486 and 488, respectively. As depicted in FIG. 14A, thenarrowed portion 484 of the shaft 482 may facilitate a low profileretracted configuration, but may also provide additional space forsnagged tissue or adhered biological material to occupy. This may occur,for example, when the elongate member 490 in FIG. 14B is retracted intoits retracted configuration in FIG. 14A, or during a prolongedprocedure. This additional space may be beneficial when withdrawingtissue removal device from an endoscopy instrument or cannula. Asfurther illustrated in FIGS. 14A and 14B, the attachments or openings486 and 488 may have a transverse axial orientation, rather than thesurface orientation of the openings 422 and 424 of the tissue removaldevice 420 depicted in FIGS. 12A and 12B.

Although the narrowed portion 484 in FIGS. 14A and 14B has a uniformdiameter and configuration, in other embodiments, such as the tissueremoval device 492 in FIG. 15, the narrowed portion 494 may have atapered configuration with a variable diameter or configuration.Referring back to FIGS. 14A and 14B, the longitudinal axis of thenarrowed portion 494 may be co-axial with the axis of the rest of theshaft 482, but in some embodiments, the longitudinal axis may bedifferent, e.g. eccentric or variable. In FIG. 16, for example, thetissue removal device 496 comprises a narrowed portion 498 with anon-linear longitudinal axis comprising a helical or corkscrewconfiguration. Also, although this example of the tissue removal device496 has narrowed portion 498 and an elongate member 399 with the samehelical orientation, in other example, the helical orientations may bedifferent or opposite.

Referring now to FIG. 5B, the tissue removal device 2 in FIG. 5A isillustrated with a portion of the housing 6 removed to show variousinternal components. In this embodiment, the tissue removal device 2further comprises a battery 12 to provide power to the motor 14 whichdrives the tissue removal assembly 8. In other embodiments, a connectorto an external power source may be provided in addition to, or in lieuof, the battery 12. The type of battery and power provided may differdepending upon the particular power needs of the motor and/or othercomponents of the tissue removal device 2.

In some embodiments, the motor 14 of the tissue removal device 2 is a DCmotor, but in other embodiments, the motor 14 may have any of a varietyof configurations, including but not limited to an AC or a universalmotor. The motor 14 may be a torque, brushed, brushless or coreless typeof motor. In some embodiments, the motor 14 may be configured to providea rotational speed of about 500 rpm to about 200,000 rpm or more,sometimes about 1,000 rpm to about 40,000 rpm, and at other times about5,000 rpm to about 20,000 rpm. The motor 14 may act on the tissueremoval assembly 8 via the outer tube 4, or a by drive member locatedwithin the outer tube 4. In some further embodiments, a fluid seal 16may be used to protect the motor 14 and/or other components of thehousing 6 from any fluids or other materials that may be transportedthrough the outer tube 4, or through the housing aperture 18. In someembodiments, a connector or seal may be provided about the housingaperture 18 to permit coupling of the housing 6 to a trocar, anintroducer, a cannula or other tubular member into which the tissueremoval assembly 8 and the outer tube 4 are inserted. In someembodiments, the tissue removal device may be used with an introducer orcannula having an outer diameter of about 0.01 cm to about 1.5 cm ormore, sometimes about 0.1 cm to about 1 cm, and other times about 2 mmto about 6 mm.

As shown in FIGS. 5A and 5B, the tissue removal device 2 may furthercomprise a conduit 24 which may be used to connect the tissue removaldevice 2 and an aspiration or suction source. An aspiration or suctionsource may be used, for example, to transport fluid or material througha lumen or conduit of the outer tube 4 or through a tubular member inwhich the outer tube 4 is inserted. In one particular embodiment, theconduit 24 comprises a port 20 which communicates with the fluid seal 16via a length of tubing 22. The fluid seal 16 is configured to permitflow of fluid or material between the outer tube 4 and the tubing 22,while permitting movement of the outer tube 4 or a drive member thereincoupled to the motor 14. In other embodiments, the conduit 24 mayfurther comprise additional components, including but not limited to afluid or material trap, which may be located within or attached to thehousing 6, or attached to the port 20 or the tubing 22, or locatedanywhere else along the pathway from the tissue removal assembly 8 tothe suction source. In some embodiments, a separate port may be providedfor infusing or injecting substances into target site using the tissueremoval device 2. In other embodiments, the conduit 24 may be used forboth withdrawal and infusion of materials and/or fluids, or for infusiononly. Depending upon the configuration of the tissue removal device,withdrawal and/or infusion may occur at the distal end of the outer tube4, and/or through one or more openings of the tissue removal assembly 8.In other embodiments, a port may be used to insert a coagulationcatheter, an ablation catheter or other energy delivery device to thetarget site.

In some embodiments, the outer tube comprises an outer tubular memberwith at least one lumen, and an elongate drive member configured tomechanically couple the motor to the tissue removal assembly. In otherembodiments, the outer tube may contain additional members, for example,to adjust or control the configuration of the tissue removal assembly.In some embodiments, the outer tube 4 may comprise one or more lumenscontaining control wires, which may be used to manipulate thedeflections of the distal end of the outer tube. The outer tube andoptional drive members may be rigid or flexible. The outer tube may bepre-shaped with a linear or a non-linear configuration. In someembodiments, the outer tube and the components are configured to beuser-deformable, which may facilitate access to particular target sites,or may be user-steerable using a steering mechanism comprising one ormore pull wires or tension elements. In some embodiments, a stiffeningwire or element may be inserted into the outer tube to provideadditional stiffness to the tissue removal device. The length of theouter tube between the tissue removal element and the motor or housingmay vary from about 0 cm to about 30 cm or more in some embodiments,sometimes about 4 cm to about 20 cm, and other times about 10 cm toabout 14 cm.

In other embodiments, the tissue removal device may comprise a tissueremoval assembly that may be detachably attachable to the shaft of amotor or coupled to a motor. In still other embodiments, the tissueremoval device may comprise a tissue removal assembly coupled to ashaft, wherein the shaft may be detachably attachable to a motor or ashaft coupled to a motor.

In some embodiments, the housing 6 is configured with a size and/orshape that permits handheld use of the tissue removal device 2. In otherembodiments, the tissue removal device 2 may comprise a grip orstructure located about the outer tube 4 to facilitate handling by theuser, while the proximal end of the outer tube 4 is attached to abenchtop or cart-based machine, for example, or a mounted or fixedmachine. In these embodiments, the grip may or may not contain any othercomponents of the tissue removal device, such as a motor, while themachinery at the proximal end of the outer tube 4 may contain one ormore other components, such as a suction system or variousradiofrequency ablation components, for example. In some embodiments,the housing 6 may have a length of about 1 cm to about 12 cm or more,sometimes about 2 cm to about 8 cm, and other times about 3 cm to about5 cm. The average diameter of the housing (or other transverse dimensionto the longitudinal axis of the housing) may be about 1 cm to about 6 cmor more, sometimes about 2 cm to about 3 cm, and other times about 1.5cm to about 2.5 cm. The housing 6 may further comprise one or moreridges, recesses or sections of textured or frictional surfaces,including but not limited to styrenic block copolymers or other polymersurfaces.

As illustrated in FIG. 17, a tissue removal device may optionallycomprise a tissue transport assembly 68, which may be used to facilitatetransport or removal of tissue within or along the outer tube 4. In theparticular embodiment depicted, the tissue transport assembly 68comprises a helical member 70 mounted on a drive member 78 that may berotated. Actuation of the drive member 78 may mechanically facilitateproximal movement of tissue or other materials within the channel or thelumen 72 of the outer tube 4 by rotating the helical member 70. Theactuated drive member 78 will also rotate the distal burr element orother tissue removal assembly 8. In some embodiments, use of the tissuetransport assembly 68 may be performed at lower rotational speeds whentissue debulking is not concomitantly performed. When rotated in theopposite direction, the helical member 70 may be used expel or distallytransport tissue, fluid or other materials or agents from the outer tube4 or supplied to an infusion port of the housing 6.

In some embodiments, the helical member 70 may have a longitudinaldimension of about 2 mm to about 10 cm or more, sometimes about 3 mm toabout 6 cm, and other times about 4 mm to about 1 cm. In otherembodiments, the longitudinal dimension of the helical member 70 may becharacterized as a percentage of the longitudinal dimension of the outertube 4, and may range from about 5% to about 100% of the longitudinaldimension of outer tube 4, sometimes about 10% to about 50%, and othertimes about 15% to about 25%, and still other times is about 5% to about15%. Although the helical member 70 depicted in FIG. 17 rotates at thesame rate as the tissue removal assembly, due to their mounting orcoupling onto common structure, drive member 78, in other embodiments,the helical member may also be configured to rotate separately fromdrive member. For example, a helical member may comprise a helical coilthat is located along at least a proximal portion of the lumen of theouter tube but is not mounted on the drive member. In this particularexample, the helical member may rotate independently of the drivemember. In still other embodiments, the helical member 70 may be mountedon the surface of the lumen 72 and can be used to transport tissue orsubstances along the lumen 72 by rotation of the outer tube 4,independent of the drive member 78 or a tissue removal assembly.

Although the helical member 70 is depicted as a continuous structure, insome embodiments, the helical member 70 may be interrupted at one ormore locations. Also, the degree or angle of tightness of the helicalmember 70 may vary, from about 0.5 turns/mm to about 2 turns/mm,sometimes about 0.75 turns/mm to about 1.5 turns/mm, and other timesabout 1 turn/mm to about 1.3 turns/mm. The cross-sectional shape of thehelical member 70 may be generally rounded as depicted in FIG. 17, butin other embodiments, may have one or more edges. The generalcross-sectional shape of the helical member 70 may be circular,elliptical, triangular, trapezoidal, squared, rectangular or any othershape. The turn tightness and cross-sectional shape or area of thehelical member 70 may be uniform or may vary along its length. In someembodiments, multiple helical members 70 may be provided in parallel orserially within the outer tube.

In some embodiments, the drive member 78 may be configured to extenddistally and retract from the outer tube 4 by a length of about 0.004inch to about 0.8 inch or more, sometimes about 0.008 inch to about 0.6inch and other times about 0.01 inch to about 0.4 inch. In someembodiments, the helical member 70 is located proximal to the tissueremoval assembly at a distance of about 0.004 inch to about 0.8 inch ormore, sometimes about 0.008 inch to about 0.6 inch and other times about0.01 inch to about 0.4 inch. In some embodiments, when drive member 78is maximally extended from outer tube 4, helical member 70 may protrudefrom outer tube 4 by a longitudinal dimension of about 0.004 inch toabout 0.8 inch or more, sometimes about 0.004 inch to about 0.4 inch,and other times about 0.1 inch to about 0.2 inch. In some embodiments,the degree of extension of the drive member 78 and/or the helical member70 may affect the degree of tissue transport by the tissue transportassembly.

Referring to FIGS. 18A and 18B, in another embodiment, a tissue removaldevice 500 comprises a housing 502 and an outer shaft 504. The housing502 may include an adjustment mechanism with a thumbwheel 506 configuredto adjust the retraction and extension of extendable tissue removalassembly (not shown). The thumbwheel 506 may provide a continuous rangeof change to extendable tissue removal assembly, but in otherembodiments, the turning of thumbwheel 506 may be configured with clicksor detents that provide one or more preset positions. As mentionedpreviously, any of a variety of other control mechanisms and interfacesmay be used. The adjustment mechanism may comprise one or more blockingelements or other adjustment limiting configurations to resist orprevent overextension of the extendable tissue removal assembly. Forexample, limit structures may be provided in housing 502 to resistoverextension of the extendable tissue removal assembly (not shown). Inthis particular embodiment, tissue removal device 500 is configured torotate the tissue removal assembly at a fixed rotational speed,controllable by a rocker-type power switch 508. As mentioned previously,however, any of a variety of power and/or speed control mechanisms maybe used.

FIG. 18C is a component view of the internal components within housing502, while FIG. 18D is a schematic cross-sectional view of the internalcomponents with a portion of housing 502 removed. As shown in FIG. 18C,a drive member 510 rotatably resides within the outer shaft 504 of thetissue removal device 500. The distal end (not shown) of the drivemember 510 is coupled to the tissue removal assembly (not shown), whilethe proximal end 512 of the drive member 510 is coupled to the distalend 514 of a driveshaft 516. The proximal end 518 of the driveshaft 516may be coupled to a motor 520, either directly or through a coupler 522.The coupler 522 may be configured to permit some axial movement ofdriveshaft 526. The proximal end 524 of an adjustment member 526protrudes from the proximal end 510 of drive member 512 and is attachedto a drive key 528. The drive key 528 may comprise a flange 530 that isslidably located between the proximal and distal ends 518 and 514 of thedriveshaft 516. The thumbwheel 506 may be movably coupled to a thrustmember 532 so that the rotation of the thumbwheel 506 results in theaxial movement of thrust member 532. In some embodiments, the thrustmember 532 may be configured with helical threads that are complementaryto a threaded lumen of the thumbwheel 506. In other embodiments,however, the thrust member may comprise a slide member, a pivot memberor other coupling structure. The thrust member 532 may be configured toaxially slide the drive key 528 through a retaining structure 534 whichmovably couples the thrust member 532 to the drive key 528. Theretaining structure 534 permits the rotation of the driveshaft 516 bythe motor 520 while also coupling the axial movements of the thrustmember 532 to the drive key 528, thereby permitting adjustment of thetissue removal assembly located at the distal end of the shaft 504 whilemaintaining the ability of the drive member 510 to rotate. The thrustmember 532 may comprise a flange 536 to facilitate retention of thethrust member 532 within the retaining structure 534. The flange 536 maycomprise one or more bearings to facilitate rotational movement of thedrive key 528 against the non-rotating flange 536. The retainingstructure 534 may also contain one or more retaining bearings 538 tofacilitate the rotation of the driveshaft 516 against the drive key 528while transmitting any axial forces to the drive key 528. The retainingstructure 534 is optionally provided with one or more limiters 540,which may be used to restrict overextension or retraction of the tissueremoval assembly. A seal 542 may be provided around the outer shaft 504to protect the contents of the housing 502.

As illustrated in FIG. 18D, the tissue removal device 500 may be poweredusing a battery 544 that is coupled to the motor 520 using a batteryconnector 546. As depicted in FIG. 18C, battery 544 may be astandardized battery, such as a 9-volt battery, but may also be acustomized battery. Other examples of drive shafts couplings andadjustment mechanisms that may be used are disclosed in U.S. Pat. No.5,030,201, which is hereby incorporated by reference in its entirety.

In the various examples described herein, the outer tube and thedriveshaft of the tissue removal device may comprise a rigid structureand material, but may also optionally comprise at least one flexibleregion which may bend while still permitting rotation of the driveshaft.Examples of flexible driveshafts that may be used are disclosed in U.S.Pat. Nos. 5,669,926 and 6,053,907, which are hereby incorporated byreference in their entirety. In some examples, the flexible region(s)may comprise a substantial portion or all of the length of thedriveshaft and outer tube. A tissue removal device with a flexibleregion may facilitate access to certain regions of the body, such as thecentral spinal canal through an intervertebral foramen. In someexamples, the flexible tissue removal device may comprise a steeringassembly that uses one or more steering wires that are attached distalto the flexible region and manipulated by a steering member in theproximal housing. Other steering mechanisms used with catheters andother elongate instruments may also be used. In other examples, anactive steering mechanism is not provided on the flexible tissue removaldevice, but the flexible tissue removal device may be steered by anendoscopic instrument into which the tissue removal device has beeninserted. Some examples of steerable endoscopic instruments aredisclosed in application Ser. No. 12/199,706, which is herebyincorporated by reference in its entirety.

FIGS. 19A to 19C depict one embodiment of a tissue removal device 600with a flexible region 602 and a steering assembly 604 located in thehousing 606 of the tissue removal device 600. In addition, the housing606 includes a power switch 608 which actuates the motor 610 thatrotates the driveshaft (not shown) located in the outer tube 612, and anirrigation tube 614 which may be used infuse fluid or provide suctionabout the distal end of the device 600. As shown in FIG. 19B, thesteering assembly 604 comprises a pivoting lever 616 with two arms 618and 620 protruding from the housing 606. In other embodiments, thesteering assembly 604 may comprise a single arm lever, a slider, knob orother type of actuator. The steering assembly 604 may optionallycomprise one or more springs or bias structures, which may facilitatespringback of the lever 616 once released. The steering assembly 604 mayalso optionally comprise a releasable locking mechanism to maintain thesteering assembly in a particular configuration. The locking mechanismmay be a frictional interfit or an interlocking mechanism, for example.

Coupled to the lever 616 are two steering elements or wires 622 and 624,which are slidably movable within the outer tube 612 and are distallycoupled to a distal site of the flexible region 602. The steering wires622 and 624 may be separate wires, or two segments of the same wirelooped through the lever 616. When a steering wire 622 or 624 istensioned by actuating one of the lever arms 618 and 620, the flexibleregion 602 will curve or bend. The flexible region may comprise any of avariety of flexible materials and/or flexible structures, including anyof a variety of polymeric or metallic structures. In the depictedembodiment, the flexible region 602 comprises a plurality of optionalslots 626, which may augment the bending characteristics, but in otherembodiments, an accordion-like configuration or other type of bendingconfiguration may be provided. The ends 628 of the slots 626 depicted inFIG. 19C have optional enlarged arcuate configurations, which mayredistribute at least some of the bending forces that may act on theflexible region 602 and may resist tearing or reduce any resultingdamage to the flexible region. The length of the flexible region may bein the range of about 0.04 inch to about 8 inches or more, sometimesabout 0.2 inch to about 2 inches, and other times about 0.3 inch toabout 0.8 inch. The width of the ends 628 of the slots 626, as measuredin the unbent configuration along the longitudinal axis of the tissueremoval device, may be in the range of about 0.02 inch to about 0.15inch or more, sometimes about 0.04 inch to about 0.1 inch, and othertimes about 0.04 inch to about 0.07 inch. In still other embodiments,the flexible region may lack a particular configuration but comprises aflexible material that has a lower durometer than the other portions ofthe outer tube. The maximum degree of bending may vary from about 5degrees up to about 10 degrees or more, sometimes about 15 degrees up to25 degrees or more, and other times about 45 degrees to about 75 degreesor more, and even about 90 degrees to about 105 degrees or more incertain embodiments. In embodiments of the tissue removal device havingbi-direction steering from its neutral axis, the maximum degree ofbending in each direction may be the same or may be different.

As depicted in FIG. 19C, the exposed proximal and distal ends 646 and648 of the flexible elongate member 630 may be coupled to the rotatableshaft assembly 632 through either openings or attachment sites locatedon the circumferential surfaces of the proximal and distal ends 646 and648. Other sites where one or both ends of the flexible elongate member630 may be coupled include but are not limited to the taper regions 642and 644, if any, or any other surface having at least some degree oftransverse orientation with respect to the longitudinal axis of therotatable shaft assembly 632. Still other coupling sites may include thereduce diameter core 634, the base 636 and the piercing element 640.

A steerable tissue removal device may be used during some procedures toincrease the region or amount of tissue removed, compared to a rigidtissue removal device, for example. In some instances, anatomicalrestrictions or increased risks of injury may limit the range with whicha rigid tissue removal device may be manipulated. FIGS. 20A and 20B, forexample, schematically depict some of the movement axes and thepotential tissue removal zones that may be achieved with a steerabletissue removal device 650. Here, a steerable tissue removal device 650with an extendable cable 652 may be inserted into a vertebral disc 653.While the steerable tissue removal device 650 and a rigid linear tissueremoval device may translate and rotate with respect to its longitudinalaxis 654, the pivoting range 656 of the rigid portion of the outer tube658 of the tissue removal device 650 (and the corresponding structure ona rigid tissue removal device) may be substantially limited because evensmall angular movements of the outer tube 658 may require substantialabsolute displacement of the more proximal portions of the outer tube658. This displacement, however, will be limited by the amount, thelocation and/or the compliance of the body tissues and structuresbetween the proximal end (not shown) and the distal end 660 of the rigidportion of the outer tube 658. In contrast, a tissue removal device 650with a flexible segment 662 located distally permits a range ofangulation or bending 664 from the longitudinal axis 654 of the tissueremoval device 650 without requiring substantial displacement orleveraging of the rigid portion of the outer tube 658. Thus, theflexible segment 662 may be able to reach tissue that is spaced apartfrom the longitudinal axis 654 with less physical effort, and may beeven be able to reach tissue that cannot be reached by pivoting a rigidportion of the outer tube 658.

In addition to the bending of the flexible segment 662, the steerabletissue removal device 650 may also access tissues located away from thelongitudinal axis 654 by increasing the extension of the extendablecable 652 along its extension range 665. The extension range 665 may becharacterized as a dimension that is perpendicular to the longitudinalorientation of the core section 668 to which the extendable cable 652 iscoupled. For example, a tissue removal device with about a 0.04 inchdiameter core and configured with an extendable cable that may beadjusted to a perpendicular distance of about 0.1 inch away from thecore can remove tissue in a zone that is about 0.27 inch in at itsmaximum diameter (i.e. 0.04 inch shaft plus 2 times 0.1 inch of therotated elongate member). In embodiments where the extendable cable isextended to a greater degree, even greater volumes or zones of tissueremoval may be achieved. Thus, by manipulating the degree of cableextension, the volume or range of tissue removal that may be performedmay be adjusted without requiring repositioning the tissue removaldevice, either by torqueing its shaft or using its steering mechanism(if any).

Because the particular tissue removal device 650 in FIGS. 20A and 20Bpermits the actuation of the extendable cable 652 while the flexiblesegment 662 is bent by providing a flexible or bendable driveshaft (notshown), the tissue removal zone 670 may be displaced away from thelongitudinal axis 654. Furthermore, because each of the movementdescribed above may be synergistically combined with one or more othermovements, even greater larger tissue removal zones may be achieved. Forexample, rotation 672 of the bent tissue removal device 650 around thelongitudinal axis 654 by torqueing the rigid portion of the outer tube658, may achieve an even larger tissue removal zone 674. The rotation672 of the bent tissue removal device 650 may occur while the extendablecable 652 is being rotated, or when the cable 652 is not rotating. Theamount of rotation 672 may be anywhere in the range of about 1 degree toabout 360 degrees or more. Any of a variety of combinations of cableextension, flexible zone bending, and outer tube rotation andtranslation may be used to achieve the desired tissue removal.

While various flexible, steerable and rigid embodiments of the tissueremoval device may be used to remove larger volumes of tissue asdescribed above, in other embodiments, a tissue removal device may beused to perform focal debulking of tissue. For example, by utilizing thesmall profile and/or the steerable features of certain embodiments ofthe tissue removal device, the tissue removal device may be moreaccurately positioned or navigated to a specific target site in a bodystructure. In some instances, the removal of lower volumes of tissue ata specific target location may be used to achieve a desired result, incomparison to the removal of a larger volume of tissue from a generaltarget location. Furthermore, by adjusting the cable or tissue removalelement relative to the shaft of the tissue removal device, the volumeof mechanical tissue removal may be adjusted relative to the shaftwithout requiring repositioning of the shaft. By removing less disctissue to reduce a herniation, for example, a larger amount ofnon-pathologic disc tissue and structural integrity of the disc may bepreserved. In some instances, relatively greater preservation of thedisc tissue may slow the rate of further disc degeneration andreherniation compared to lesser degrees of tissue preservation.

In one example, a herniated disc may be accessed and visualizedendoscopically. A steerable tissue removal device may be inserted intothe disc and steered toward the region of herniation, rather than to thecenter of the disc, for example. The extendable cable or otheradjustable tissue removal element is actuated to pulverize an initialamount of tissue at the region of herniation and removed by the auger.In some embodiments, to facilitate controlled volume tissuepulverization, the distance between the couplings of the extendablecable to its rotatable shaft may be less than about 0.4 inch, sometimesless than about 0.3 inch, and other times less than about 0.2 inch. Tofacilitate precise removal of the pulverized tissue, the distal suctionopening of the tissue removal device may be located less than about 0.4inch from the proximal coupling of the extendable cable, sometimes lessthan about 0.3 inch, and other times less than about 0.2 inch or about0.1 inch. After the initial actuation of the extendable cable, theherniation is reevaluated endoscopically and the degree of cableextension may be adjusted higher in a stepwise manner and reevaluateduntil the desired reduction in the herniation is achieved.

In some uses of the tissue removal device, in both steerable andnon-steerable configurations, the tissue removal zones may positionedwhereby structures such as the annulus fibrosus and the vertebral bodyendplates may be unintentionally damaged or contacted. In embodimentswhere the tissue removal device has been configured as describedpreviously to limit or avoid significant damage to these structures,greater tissue removal may be safely achieved even when the distal tipof the tissue removal device cannot be directly visualized, e.g. whenthe endoscope is located in the epidural space while the tissue removaldevice is located inside the vertebral disc.

In some instances, embodiments of the tissue removal device may becharacterized by the ratio of the maximum diameter or cross-sectionalarea of tissue removal of a rotating extended elongate member, and thediameter or cross-sectional area of the outer tube of the tissue removaldevice or the tissue pathway formed by the tissue removal device. In theexample described above, the diameter of the elongate member in itsrotating deployed configuration to the diameter of the outer tube is aratio of about 7:1. In some embodiments, this ratio is at least about3:1 or higher, but in other embodiments, the ratio is at least about 5:1or higher, or even about 10:1 or about 20:1 or higher in certainembodiments. In other examples, the tissue removal device may becharacterized by the maximum perpendicular distance that the elongatemember may be extended, or by the ratio of this distance to the diameter(or an axial transverse dimension) of the outer tube. In some examples,this ratio is at least about 3:1 or more, sometimes about 5:1 or more,or even about 7:1 or about 10:1 or more.

Examples of procedures that may be used to access the spine aredisclosed in U.S. Pat. Nos. 7,108,705, 4,573,448, 6,217,509, and7,273,468, which are hereby incorporated by reference in their entirety.The various embodiments of the tissue removal device disclosed hereinmay be used to perform a discectomy or nucleotomy, but may also be usedto perform any of a variety of tissue removal procedures in the spineand outside of the spine. The tissue removal device may be used inminimally invasive procedures as well as open surgical procedures orlimited access procedures. These procedures may include but are notlimited to interlaminar, translaminar and intralaminar accessprocedures. In one particular embodiment, a patient may be placed into aprone position with a pillow or other structure below the abdomen tolimit lumbar lordosis. The patient is prepped and draped in the usualsterile fashion and anesthesia is achieved using general, regional orlocal anesthesia. Under fluoroscopic guidance, a sharp tipped guidewire,or a needle with a guidewire may be inserted into the paravertebralspace or epidural space from a posterior or postero-lateral location ofthe patient's back at a location in the range of about 2 inch to about 6inches lateral to the midline. In some instances, guidewire insertionmay be facilitated by inserting a needle into the tissue first. Inalternate embodiments, an anterior procedure through the abdominalcavity or anterior neck region may be performed. Once access to thetarget location is confirmed, a dilator may be used with the guidewireto enlarge the insertion pathway. Then, an introducer or cannula may beinserted over the guidewire, followed by subsequent guidewire removaland insertion of an endoscope into the introducer or cannula.Alternatively, an endoscope may be inserted over the guidewire. Theendoscope may be manipulated or steered to directly visualize andidentify the relevant structures such as the disc, the nerve or otheradjacent structures and site(s) of tissue removal. In some embodimentswhere the patient is under local or regional anesthesia, the suspectednerve impingement may be confirmed by contacting or manipulating thesuspected nerve with the endoscope, or other device inserted through theendoscope, and assessing the patient's response or symptoms. Oneembodiment of an endoscope that may be used is described in U.S.application Ser. No. 12/199,706, which has been hereby incorporated byreference in its entirety. Once the target region has been evaluated, atissue removal device may be inserted through the spinal access deviceor endoscope and to pierce through the annular wall of a herniated disc.Once inserted, the tissue removal device is manipulated the elongatemember to its extended or deployed configuration and actuated toemulsify or pulverize the tissue of the nucleus fibrosus. In someembodiments, the tissue removal device may be actuated for a duration inthe range of about 5 seconds to about 90 seconds or more, sometimesabout 15 seconds to about 60 seconds, and other times about 30 secondsto about 60 seconds. The pulverized material may then be suctionedthrough the device and then the effect of the tissue removal may bere-evaluated by the endoscope or other visualization mechanisms. In someembodiments, a liquid or lubricant may be injected or infused into thetreatment site. In some examples, the liquid or lubricant may be usefulto facilitate removal of the pulverized material, including but notlimited to vertebral discs that may be desiccated. In other examples,the liquid or lubricant may be injected or infused before or during theactuation of the tissue removal device. In some examples, the liquid orlubricant may comprise a contrast agent that may facilitate viewing ofthe tissue site on fluoroscopy, x-ray, CT, MRI, ultrasound or otherimaging modalities. The contrast agent may be used at any time or atmultiple times during the procedure, including but not limited toconfirmation of guidewire or tissue removal device placement, and alsoto verify the volume and/or location of tissue removal. In some specificembodiments, actuation of the tissue removal device may be stopped toverify that the annulus of the vertebral disc or the cortical bone ofthe vertebral body has not been compromised. Also, in some examples, thecontrast agent may be injected and imaged after device actuation toassess proper operation of the device, including but not limited totissue pulverization and aspiration mechanisms.

During actuation, the tissue removal device may be held in place or maybe moved around the treatment site. The movement may include moving thedevice back and forth along its insertion access, side to side, up anddown, or with an orbital motion (clockwise or counterclockwise), or anycombination thereof. The range of cable displacement from the rotatableshaft may also be cyclically varied during device actuation. The cyclingmovements may be performed based upon tactile feedback or rotationalresistance of the device, or may be done in repeating motion with anaverage frequency in the range of about one complete motion about every0.5 sec to about 4 seconds, about 1 second to about 2 seconds, or about0.5 seconds to about 1.5 seconds, for example. The duration of eachcycling period may be in the range of about 1 second to about 30 secondsor more, about 3 seconds to about 20 seconds, about 5 seconds to about10 seconds, for example. Suction or aspiration may be applied duringthese motions to assess the amount of tissue pulverized and removed.

The actuation of the tissue removal device may be repeated as desired toremove disc material. In some embodiments, the tissue removal device maybe withdrawn from the disc and reinserted directly into or against theextruded disc material and actuated. Once the tissue removal iscompleted, the tissue removal device may be withdrawn. The puncture sitein the annular wall may have a cross-sectional area of less than about0.003 inch² or less, sometimes about 0.0016 inch² or less, and othertimes about 0.001 inch² or less, and thus may self-seal withoutrequiring treatment of the puncture location with an adhesive, a sutureor coagulation probe. The body location may be rechecked with theendoscope or spinal access device to verify that no bleeding orcompromise of the integrity of the disc or spinal nerves has occurred,and then the endoscope or spinal access device is removed from the bodyand the skin access site is bandaged.

While the embodiments described above may be used to remove soft tissuewithout substantially removing calcified or bony tissue, in otherembodiments, the tissue removal device may be configured to remove bone.In some examples, this may include configuring the tissue removal devicewith various bone-removing coatings and/or a higher rotational speed.The coatings may comprise coarser grit structures made from materialsincluding, but not limited to titanium nitride, chrome alloy coating,tungsten carbide, diamond grits, silicon carbide grits, ceramics, orother suitable materials. The spiral cable may be spun at high speed(e.g. about 10,000 rpm to about 30,000 rpm or more) to grind the bone tosmaller pieces that can be aspirated by the auger. Saline irrigation maybe used to clean and/or cool the spiral cable and/or the surroundtissue. In some further configurations, the tissue removal device may befurther configured to differentially removing cancellous bone whilegenerally preserving compact bone. Such a tissue removal device may beused, for example, to form a passageway or cavity within a vertebralbody or a long bone without disrupting the integrity of the outersurface of the bony structure.

In one example, a hollow needle or trocar may be passed through thespinal muscles until its tip is precisely positioned within thefractured vertebra. This may be performed under external imagingguidance (e.g. fluoroscopy, CT or ultrasound) or using an endoscopysystem. In other examples, intraosseous venography may be performed inconjunction with other visualization modalities. In some instances,intraosseous venography may be used to visualize the basivertebralvenous plexus or a paravertebral vein and to possibly avoid inadvertententry into these structures.

Upon reaching the outer surface of the vertebral body, the distal tip ofthe tissue removal device (e.g. the distal head 336 of the tissueremoval device 300 in FIG. 8) may be used to penetrate the compact boneof the vertebral body to provide access to its interior. In otherembodiments, a bone penetration device, such as a trephine or a burr,may be used to form a channel or passageway into the vertebral body. Thebone penetration device is then removed and the cable-based tissueremoval device may be inserted into the passageway and into thevertebral body. In other embodiments, the tissue removal device may beprovided with a distal burr or drill head rather than a conical head. Insome examples, the spiral cable is displaced radially outward before therotating is initiated, while in other examples, rotation is initiatedfirst before the spiral cable it let out. In some examples ofvertebroplasty, the spiral cable may have a maximum radial displacementof about 0.15 inch, about 0.2 inch, about 0.25 inch, about 0.28 inch, orabout 0.4 inch or more. In some examples, the volume of space formed bythe tissue removal device may be further augmented similar to the rangeof tissue removal disclosed for removal of annular tissue depicted inFIGS. 20A and 20B. As mentioned previously, the spiral cable may berotated in the directional sense as the spiral configuration, but mayalso be rotated in the opposite direction.

The spiral cable may be as a single filament or a multi-filament cable.Each filament may comprise the same or a different material orconfiguration. In some examples, each filament comprises stainless steel(e.g. 304, 316 or 17-4 stainless steel) which is wound into a cable. Thestiffness of the cable may be altered by the changing the tightness ofthe winding, the number of filaments, and/or the thickness of thefilaments. One or more of these characteristics, in combination with anoptional grit surface may be used to adjust the preferential grindingfeatures of the tissue removal device. In some procedures, bypreferentially cutting the cancellous bone while preserving the compactbone, the compact bone shell or structure of the vertebrae or other bonemay protect the soft tissue structures located outside the shell orsurface. The compact bone shell or structure may also restrict flow ofany bone cement injected into the target site. In some examples,contrast dye or other visualization agents may be injected into thetarget site to assess the integrity of the target site prior to cementinjection or other treatments.

In another example, depicted in FIGS. 21A to 21D and FIG. 22, the tissueremoval system 700 may comprise an extendable spiral cable 702 with ablunt distal tip 704. In some instances, a blunt distal tip 704 may beused when a passageway or channel has been previously formed, or whenblunt dissection is sufficient. For example, during a discectomy or avertebroplasty procedure, a cannula 706 containing a removable obturatorwith sharp distal end 708, as shown in FIG. 23, may be used to form apassageway or channel through the tissue surrounding the spine and/orthrough the surface of a vertebra. The obturator may be removed from thecannula 706 to insert the tissue removal system 700. In other examples,a trocar with a sharp distal end may be used to form a passageway andthen removed to permit insertion of the tissue removal system 700.Alternatively, a trephine or bone burr, which may be either motorized ormanually activated, may be used with the cannula 706, in addition to orin lieu of the obturator. The cannula 706 may comprise an optionalproximal connector 709, such as Luer lock, to releasably couple theobturator and/or the tissue removal system 700. Additional variations ofcannulas and stylets that may be used to create a passageway through thetissue to the spine and/or through the surface of a vertebra will bedescribed later.

Referring to FIG. 21A, which depicts the spiral cable 702 in an extendedposition, and to FIGS. 21B to 21D, which depicts the spiral cable 702 ina retracted position, the cable 702 is attached distally to the bluntdistal tip 704 and proximally to a base 710. The cable 702 may bepartially recessed in channels 712 and 714 of the tip 704 and base 710.Between the tip 704 and base 710 is a cable shaft 716 with across-sectional size that is smaller than the tip 704 and/or base 710.In other embodiments, the cable shaft may have a cross-sectional sizethat is similar to or greater than the tip 704 or base 710. The cableshaft may also comprise an optional groove or recess to at leastpartially retain the cable 704 when in a retracted position.

FIGS. 21A to 21D further depict an optional feature of the tissueremoval system 700 comprising an outer tubular shaft 718 with a cuttingedge 720. In this particular example, the cutting edge 720 is a bevelededge, which may or may not be at least partially sharpened. In otherexamples, the cutting edge may be sharpened but not beveled. As furtherdepicted in FIGS. 21A to 21D, the inner shaft 722 located in the outertubular shaft 718 may comprise at least one optional thread structure724 which is configured to draw fluids and/or other materials into theouter tubular shaft 718 for removal from the target site. A beveled orsharpened edge may further shear or break-up materials pulled into theouter tubular shaft 718 by the thread structure 724. In some examples,the rotational sense of the thread structure 724 may be the same as thespiral cable 702, but in other examples, the thread structure 724 andthe spiral cable 702 may be opposite rotational senses.

The thread structure 724 may be made from the same or a differentmaterial as the inner shaft 722 and/or the outer tubular shaft 718. Insome examples, use of a different material between the thread structure724 and the outer tubular shaft 718 may reduce or eliminate gallingeffects from the relative rotation between the two structures. In someinstances, galling may generate dark or black materials that may pigmentthe pulverized material. This pigmentation may interfere with variousanalyses of the pulverized material, and/or the ability of the user toassess heat-related effects of the tissue removal device on thepulverized tissue. In one specific example, the outer tubular shaft 718may comprise 304 stainless steel while the thread structure 724 maycomprise 17-4 stainless steel. The thread structure 724 may beintegrally formed with the inner shaft 722, e.g. grounded or formed froma base hypotube structure, but in other examples the thread structure724 may be attached to the inner shaft 722 by welding, adhesives orother attachment processes. For example, the thread structure 724 maycomprise a coiled stainless steel or Parylene wire that may be attachedusing epoxy along its entire length to the inner shaft 722 or may beattached at certain locations, e.g. the proximal end and the distal endof the thread structure 724. In some instances, partial attachment ofthe thread structure 724 to the shaft 722 may permit greater flexion orother deformation of that section of the tissue removal system 700 bypermitting greater tensile or compressive strain in the thread structure724 compared to the inner shaft 722. This greater flexion may alsoreduce heat generation between the thread structure 724 and inner shaft722.

FIG. 21E schematically depicts another example of a cutting mechanismwhere instead of a cutting edge 720 located at the distal opening of theouter tubular shaft 718 as depicted in FIGS. 21A to 21D, the tissueremoval system may comprise an internal cutting or grinding mechanism750. This mechanism comprises an outer tubular shaft 752 with an innercutting or grinding structure 754 that protrudes into the inner lumen756 of the outer tubular shaft 752 and cooperates with a circumferentialgroove or recess 758 on the inner tubular shaft 760 to morcellize, cutor otherwise breakdown any larger tissue fragments that may enter theouter tubular shaft 752. The inner cutting structure 754 may have any ofa variety of configurations, including different rake angles and/orsurface configurations. The configuration of the recess 758 on the innertubular shaft 760 may vary in width and cross-sectional shape. Althoughonly a single internal mechanism 750 is depicted, in other examples,multiple mechanisms may be provided along the shafts 752 and 760. Insome further examples, an internal mechanism 750 may be used with thetip-based mechanism illustrated in FIGS. 21A to 21D.

FIG. 22 further depicts another optional feature of a tissue removalsystem 700, comprising an optically transparent chamber 726. Althoughthe optically transparent chamber section 726 in FIG. 22 is locateddistally at the attachment of the outer tubular shaft 718, in otherexamples, the optically transparent housing chamber 726 may be locatedat a more proximal location. The optically transparent housing section726 comprises an optically clear passageway or cavity in communicationwith the lumen of the outer tubular shaft 718 so that any fluid and/ormaterials either injected distally or removed proximally may be viewedby the user. In some instances, the passageway or cavity may have avolume of at least about 0.5 cubic centimeters, sometimes about 1 cubiccentimeter, and other times about 2 cubic centimeters or 15 cubiccentimeters or more. The quantity of fluid or tissue that may becontained within the optically transparent chamber may be less than orequal to the total volume of the chamber. For example, the total volumeof an optically transparent chamber may be about 15.0 cubic centimeters,but may be configured to collect up to 10.0, 12.0, or 14.0 cubiccentimeters of material. The optically transparent housing chamber 726may also comprise markings to identify the volume of material that hasaspirated or prepared for infusion or irrigation, for example. Theoptically transparent chamber 726 may also feature a port with aremovable cap to empty the contents of the chamber 726, to reduceclogging or to collect a diagnostic tissue sample. In some examples, thetissue removal system may have one or more infusion lumens with one ormore openings at the base, cable shaft, and/or distal tip of the tissueremoval system, which may be used in addition to or in lieu distal endof the outer tubular shaft 718. In other examples, the tissue removalsystem may be removed from the vertebral body and a separate infusioninstrument may be used to deliver therapeutic agents or materials.

Another variation of a tissue removal device is shown in FIG. 35A. Thistissue removal device 3500 comprises a handle 3502, a collection chamber3504 which is located at a distal portion of the handle 3502, an outertube 3508 extending from the handle through the collector 3504, a travellimiter 3506 slidable over the outer tube 3508, and a tissue removalassembly 3510 attached to a distal portion of the outer tube 3508. Thetissue removal assembly 3510 further comprises an elongate member 3511,as described previously. In other embodiments, the collection chambermay be located elsewhere with respect to the handle, or may beseparately attachable to a port or conduit of the handle. Additionalvariations of tissue removal assemblies and configurations are describedbelow.

The outer tube 3508 may be used to provide a conduit between the distaltissue removal assembly 3510 and the collection chamber 3504 and/orhandle 3502 via a longitudinal lumen therethrough. As describedpreviously, the outer tube may be flexible, steerable, deformable,and/or bendable, as appropriate for directing the distal tissue removalassembly to the target tissue. Different flexibilities and curvatures ofthe outer tube may help the tissue removal device to access spinaland/or vertebral tissue, or another particular region of the body. Forexample, the outer tube 3508 may have one or more malleable or flexibleregions along its length, which may provide additional maneuveringcapability to a practitioner. In some variations, there may be one ormore slotted regions along the outer tube that facilitate bending orflexing of the tube. The orientation of the slots, e.g., transverseslots, angled slots, axial slots, etc. may provide the outer tube topreferentially bend in certain directions. While the outer tube 3508 isdepicted to be substantially straight, in other variations, an outertube may have one or more pre-shaped curves, where the curves may besubstantially rigid or substantially flexible. For example, a straightor curved access pathway to the target tissue may be additionallyadjusted and/or shaped by the curvature of the outer tube. In somevariations, access to the target tissue may be provided through astraight or curved cannula. An outer tube with one or more flexiblecurved regions may be straightened by sliding it into a straightcannula, or flexed by sliding it into a curved cannula. Alternatively,an outer tube with rigid curved regions may be inserted into a bendableflexible cannula and cause it to curve along the curved regions. Inother variations, the outer tube may be flexed or otherwise manipulatedusing a steering mechanism as previously described.

The outer tube 3508 may have a tensile modulus of about 2500 MPa toabout 4500 MPa, and a tensile strength greater than about 60 MPa. Theouter tube may have an inner diameter of about 1 mm to about 1.5 mm, forexample, 1.25 mm, and an outer diameter of about 1.3 mm to about 1.6 mm,e.g., 1.4 mm. The thickness of the outer tube wall may be from about0.05 mm to about 1 mm, e.g., 0.075 mm. The outer tube may have a lengthfrom the tissue removal assembly to the handle housing of about 100 mmto about 500 mm, for example, at least length of about 300 mm or about400 mm, etc.

The location of the travel limiter 3506 on the outer tube 3508 and thelength of the outer tube may determine the working length of the tissueremoval device 3500. For example, the travel limiter 3506 may be locatedat a position along the outer tube 3508 such that the tissue removaldevice has a working length between 4 inches and 20 inches, e.g., 6.5inches or 7 inches. Some variations of an outer tube may have a diameterthat is suitable for the insertion of an endoscope therethrough, so thatthe procedure, e.g., discectomy, may be directly visualized. Forexample, an outer tube may have a lumen through which an endoscope maybe inserted. The one or more visualization lumens may be locatedalongside the outer tube, or may be an internal lumen of the outer tube.Some outer tube variations may be a hypotube or a multifilament braidedor coiled cable. The filaments of the coil or braid in the outer tubemay be about 0.001 inch to about 0.007 inch wide, and about 0.01 mm toabout 0.1 mm thick. The outer tube 3508 may be made of a metal such as304 stainless steel, a metal alloy such as nickel titanium alloy, or apolymer, such as polyimide, or a combination thereof, and may compriseany of a variety of structural configurations. For example, the outertube may comprise a braided or extruded polyimide. Certain variations ofan outer tube may be coated with an additional material to help preventgalling effects, and/or to provide thermal insulation, which may helpprevent thermal damage to any tissue structures.

The handle 3502 may comprise a control interface that may be used tocontrol the power state and the use of the tissue removal device 3500.The control interface may comprise a slider 3522 and a rocker-type powerswitch 3524, as illustrated in FIGS. 35A and 35B. The slider 3522 mayregulate the configuration and use of the tissue removal assembly 3510.Other handle variations may comprise one or more push buttons, sliders,dials, or knobs. The handle housing 3530 may be ergonomically sized andshaped, such that the various components of the control interface may bereadily accessed and actuated by a user. For example, the handle housing3530 has a first recessed region 3526 and a second recessed region 3528,where the first and second recessed region are located to be suitablefor a hand-hold such that the slider 3522 and the power switch 3524 maybe actuated by the fingers of the same hand. The handle housing 3530 mayalso comprise one or more ridges, recesses or sections of textured orfrictional surfaces, and may have components and dimensions similar tothe variations of handles previously described.

FIGS. 36A to 36E depict a perspective view of the handle 3500 with aportion of the handle housing 3530 removed and various component viewsof the internal mechanisms of the handle 3500. The mechanisms may serveany of a variety of function. For example, some mechanisms may controlthe navigation of the tissue removal assembly 3510, as well as controlthe configuration of the elongate member between a retracted state andan extended state. One mechanism that may be used to transition theelongate member from a retracted state and an extended state while beingrotated by a motor has been previously described in FIGS. 18C and 18D.Another variation of such a mechanism is depicted in FIGS. 36A to 36Eand described below. FIG. 36A illustrates a rotatable shaft 3606 that iscoupled to a motor 3604 that is configured to rotate the tissue removalassembly at rotational speeds previously described. The motor 3604 maybe powered by a battery 3602, e.g., a 9 volt battery, or may be coupledto an external power source. The operating range of the motor 3604 maybe between 1.5 to 4.5 volts, nominally with a 3 volt constant.

The tissue removal device may be configured to provide a rotatable shaftwith an axially extendable and retractable mechanism to alter theconfiguration of the elongate member 3511 located distally. For example,a rotatable shaft 3606 may be rotatably maintained in the handle with afirst ball bearing 3610 and a second ball bearing 3612. The ballbearings may be configured to facilitate rotation of the rotatable shaft3606. The second ball bearing 3612 is retained within a retainingstructure 3613 that is affixed to the handle housing 3530, while, thefirst ball bearing 3610 may be movably retained in a retaining structure3614 that is affixed to the slide actuator 3522. A coupler 3608 may beprovided along the rotatable shaft 3606, where the coupler 3608 isconfigured to slide along the length of the rotatable shaft 3606 andinterfaces with the movable first ball bearing 2610. The displacement ofthe coupler 3608 along the shaft 3504 by the first ball bearing 3610provides movement of structures within the rotatable shaft while alsopermitting rotation of the coupler 3608 and the shaft 3606 within thefirst ball bearing 3610. Together, this configuration permits axialtranslation of the elongate member within the rotatable shaft 3606during rotation. In some variations, the coupler 3608 may be attached tothe proximal section of the elongate member 3511 of the tissue removalassembly 3510, whereby manipulation of the slide actuator 3522 resultsin reconfiguration of the elongate member 3511 between a retracted stateand an extended state while rotating.

FIGS. 36B-36E provide additional details of the mechanism by which anelongate member that is housed within the rotatable shaft 3606 may betransitioned between an extended and retracted configuration duringrotation. FIGS. 36B and 36C depict a side view and a side perspectiveview of the mechanism when the elongate member is in a retractedconfiguration. The rotatable shaft 3606 extends from the second ballbearing 3612 through the first ball bearing 3610 and is connectedproximally to the motor 3604 via a motor connector 3605. The rotatableshaft 3606 may be soldered, welded, brazed, heat bonded, chemicallybonded, snap fit, mechanically attached (e.g. set screw, press fit,swaged, crimped, etc.) or otherwise securely and fixedly attached to themotor connector 3605. As described previously, the coupler 3608 may beslidable along the rotatable shaft 3607, and may couple an elongatemember within the shaft (not shown) to the shaft with a pin 3609 suchthat the elongate member may rotate as the rotatable shaft is rotated bythe motor. For example, an elongate member within the shaft may becoupled to the pin 3609 via a metal lug that is slidably disposed withinthe rotatable shaft 3606. The rotatable shaft 3606 may comprise alongitudinal slot 3607 that extends along a length of the shaft. Thelength of the slot 3607 provides a range of movement for the coupler3608, and may be from about 0.25 inch to about 2 inches, for example,0.6 inch. Sliding the slider 3522 in the direction of arrow 3630 pushesthe first ball bearing 3610 retained by the retaining structure 3614 inthe same direction. The first ball bearing 3610 then pushes against theslidable coupler 3608, which is also urged in the direction of the arrow3630 along the slot 3607. Displacement of the slidable coupler 3608distally (as illustrated by arrow 3630), results in the distaldisplacement of the elongate member within the rotatable shaft 3600.FIGS. 36D and 36E depicts the coupler 3608 in a distalmost position ofthe slot 3607 after maximum distal actuation of the slider 3522. Theslider 3522 may also be moved proximally (as illustrated by arrow 3632)to transition the elongate member back to the retracted configuration.An optional spring member 3603 that may be attached to the handlehousing 3530 may bias the slider 3522 to a distal or proximal location,and/or may help the slider 3522 snap into position as the slider isurged according to the arrow 3630.

The tissue removal device 3500 may also comprise an opticallytransparent chamber, as described above. For example, as depicted inFIG. 37, the tissue removal device 3500 comprises a collection chamber3504. The collection chamber 3504 may comprise one or more collectionports 3702 with a removable cap or plug. The collection port 3702 isshown to be circular, but may be rectangular, triangular, hexagonal,etc., as appropriate. The collection port 3702 may have a diameter fromabout 0.06 inch to about 0.28 inch, e.g., about 0.07 inch to about 0.25inch. Tissue and/or fluid may be delivered from the target tissue siteto the collector 3504 via a tissue transport assembly, one variation ofwhich has been described above, and additional variations will bedescribed below. Alternatively or additionally, a vacuum source may beused to draw tissue and/or fluid from the target tissue site to thecollector. Optionally, a portion of the collection chamber 3504 may be aconfigured as a magnifying lens which may be used to visually inspectany collected samples. In some variations, the collection port plug orcap itself may be a magnifying lens.

A tissue removal device 3500 may also comprise a travel limiter 3506, asshown in FIG. 37, and enlarged in FIG. 38A. A travel limiter may be usedto constrain and/or define the range of axial and rotational movement ofa tissue removal device after it has been inserted into a patient. Forexample, a travel limiter may be configured to regulate and/or restrictthe position and orientation of the tissue removal assembly locateddistal to the outer tube. Some variations of a travel limiter may beconfigured to be fixedly connected to an access cannula, which may actas a reference point around which the tissue removal assembly may bepositioned. Travel limiters may have a number of configurations thatallow varying degrees of motion to the tissue removal device. Forexample, in a first configuration, the distal portion of a tissueremoval device may be constrained to axial movement of up to 13.5 mm,and a second configuration where the tissue removal device may beconstrained to axial movement of up to 18.5 mm. In a thirdconfiguration, the tissue removal device may be restrained from anyaxial movement. In certain configurations, the travel limiter may allowthe position and/or orientation of the tissue removal assembly to beadjusted along two or more degrees of freedom, e.g., adjusted axiallyand/or perpendicularly to the longitudinal axis of the device, and/orrotated around the longitudinal axis of the device. In otherconfigurations, the travel limiter may immobilize the device so that itcannot be repositioned, or may constrain the movement of the device suchthat it may only be repositioned along one degree of freedom, e.g.,perpendicular to the longitudinal axis of the device. Immobilizing orconstraining the movement of the tissue removal device after insertioninto a patient may help prevent accidental withdrawal of the device, orunintentional shifts in location or orientation, which may damageperipheral tissue and neural structures. For example, restricting themovement of the tissue removal device during a vertebral disc proceduremay be a desirable safeguard against damage of nearby nerves byunintentionally twisting, rotating, pulling, or pushing the tissueremoval assembly.

One variation of a travel limiter 3506 comprises a grooved tube 3802, alatch 3806 that is slidable over the grooved tube 3802, and a slide tube3808 that is slidable over the body of the grooved tube 3802 aspermitted by the latch 3806. The slide tube 3808 may also rotate aroundthe grooved tube 3802. The slide tube 3808 may also comprise a connector3810 that is configured for the attachment of cannula, stylets, tubes,etc. as desired. A cannula that is attached to the slide tube 3808 viathe connector 3810 may move in conjunction with the slide tube 3808,e.g., sliding and/or rotating the slide tube 3808 may also slide and/orrotate the cannula. In other variations, the cannula may be in a fixedposition, and engaging the travel limiter fixedly with the cannula mayallow the tissue removal device to slide and rotate with respect to thecannula position. The connector 3810 may be a friction-fit, snap-fit,screw-fit, or Luer-Lok™ type connector. The slide tube 3808 comprisesone or more grips 3812 around the perimeter to enable a user totranslate the slide tube 3808 over the grooved tube 3802. The connecter3810 may have an aperture and/or channel configured to pass the outertube 3508 through the slide tube 3808. The connector channel may extendpartially or entirely across the length of the slide tube 3808, withinthe slide tube lumen 3814. A component perspective view of the slidetube 3808 is illustrated in FIG. 38B, which shows the slide tube lumen3814, with inwardly pointing serrated locking features 3816 arrangedaround the circumference of the lumen 3814. There may be any suitablenumber of serrated locking features 3816, for example, 2, 3, 4, 5, 6, 8,9, 10, 12, 15, 16, 20, etc., serrations that may be used to restrainrelative motion between the slide tube 3808 and the grooved tube 3802.

The grooved tube 3802 comprises a tube body 3820 with a tube stop 3822attached at the distal portion of the tube body 3820. The proximalportion of the grooved tube 3802 may be fixedly attached to the distalportion of the collector 3504. In some variations, the grooved tube andthe collector may be integrally formed. The grooved tube body 3820 mayhave one or more grooves, for example, a first groove 3804 and a secondgroove 3805, and a grooved tube lumen 3818 through the tube body. Thetube lumen 3818 may be located and shaped to receive the outer tube 3508that may be inserted through the slide tube 3808. The grooves may extendaround the perimeter of the tube body, e.g., along the outer surface ofthe tube body 3820. The axial movement of the slide tube 3808 over thegrooved tube 3802 may be determined in part by the spacing between thefirst and second grooves, as will be described in detail below. Thespacing between the first groove 3804 and the second groove 3805 may befrom about 1 mm to about 10 mm, for example, 5 mm. The tube stop 3822may have one or more locking feature mates 3818 that are configured toengage the locking features 3816 of the slide tube 3808. While the tubestop 3822 has two locking feature mates 3818 (the first is shown in FIG.38B, and the second is located directly opposite the first lockingfeature mate), other variations may have 1, 3, 5, 6, 8, 9, 10, 12, 15,16, 20, etc., locking features mates. When the locking features 3816 areengaged with the locking feature mates 3818, the slide tube 3808 isrestrained from rotating around the grooved tube 3802. For example, whenthe locking feature 3818 is engaged between the serrations of thelocking feature 3816, the slide tube 3808 is rotatably locked with thegrooved tube 3802, i.e., the slide tube is no longer rotatable aroundthe grooved tube.

The slide tube 3808 and grooved tube 3802 may be sized and shaped suchthat the slide tube may slide along and/or rotate over the grooved tube.For example, the slide tube 3808 may have a length L1, where L1 is about0.5 inch to about 2 inches, a first diameter D1, where D1 is about 0.35inch to about 1.5 inches. The lumen 3814 may have a diameter that is thesame as, or less than, D1. The opening 3824 to the lumen may have asecond diameter D2, where D2 is less than D1, for example, about 0.2inch to about 1 inch. The tube stop 3822 has a diameter D3, where D3 maybe less than or equal to the diameter D1 of the slide tube 3808, butgreater than the diameter D2 of the opening 3824. The diameter D3 may befrom about 0.3 inch to about 1.25 inch, for example, 0.44 inch. The tubebody 3820 has a diameter D4, where D4 may be less than or equal to thediameter D2 of the opening 3824. The diameter D4 may be from about 0.1inch to about 1 inch, for example, 0.34 inch. In the variation of thetravel limiter 3506 depicted in FIG. 38A, the connector 3810, slide tube3808, and the grooved tube 3802 may be configured as shown in FIG. 38C.The connector 3810 and collector channel 3824 may be affixed within theslide tube 3808. In this variation, the grooved tube body diameter D4 isless than the slide tube opening diameter D2, which may allow the slidetube 3808 to slide over the grooved tube 3802. The connector channel3824 may have a diameter D5 that is smaller than grooved tube bodydiameter D4, so that it may be inserted into the grooved tube lumen3818. However, the tube stop diameter D3 may be greater than the openingdiameter D2, so that the grooved tube 3802 is retained within the lumenof the slide tube. Other arrangements may also be used where the slidetube may be moved with respect to the grooved tube, and limited by thetube stop.

In some variations, one or more sleeves may surround outer tube 3508 inthe location of the slide tube 3808. The sleeve or sleeves may, forexample, help to control movement (e.g., sliding) by the slide tube. Incertain variations, such a sleeve may have a length of about 20 mm toabout 40 mm (e.g. 30 mm), an inner diameter of about 0.03 inch to about0.07 inch (e.g. 0.05 inch), and/or an outer diameter of about 0.04 inchto about 0.08 inch (e.g. 0.058 inch). Exemplary materials that may beappropriate for such a sleeve include metal alloys such as stainlesssteel (e.g. grade 304 stainless steel). Sleeves may, of course, be usedin other tissue removal devices described herein, as appropriate.

While the slide tube 3808 and the grooved tube 3802 may comprise arounded and cylindrical configuration, other variations of slide tubesand grooved tubes may have other suitable geometries, such astriangular, rectangular, hexagonal, octagonal, etc. In some variations,the slide tube 3808 may be made of an optically transparent material,such as polyethylene terephthalate (PET), nylon, polycarbonate,polyethylene, acrylonitrile butadiene styrene (ABS), polypropylene, andthe like, while in other variations, the slide tube may be opticallyopaque. Optionally, the surfaces of the slide tube and the grooved tubemay be coated with a friction-modification agent, which may eitherincrease or decrease the friction between the surfaces. It may bedesirable in some variations to increase the frictional forces betweenthe sliding surfaces to help prevent slippage, while in othervariations, the frictional forces may be reduced to facilitateadjustment of the slide tube.

A perspective view of the travel limiter 3506 is shown in FIG. 38D,where the slide tube 3808 is slidably coupled over the grooved tube 3802as previously described. Additionally, the latch 3806 is slidablycoupled over the grooved tube 3802. The position of the latch 3806 alongthe length of the grooved tube 3802 may define the range of relativemovement between the slide tube and the grooved tube. For example, theslide tube 3808 of the tissue removal device 3500 may be fixedlyattached to an access cannula that is inserted within a patient. Thelocation of the latch 3806 along the grooved tube 3802 which may befixedly attached to the handle defines the movement range of the tissueremoval device with respect to the access cannula. The latch 3806 maycomprise a circular bracket 3828 that is fitted between the two platesof a latch base 3830. The latch base 3830 may also comprise a latch baselumen 3836 that is sized and shaped to fit over the grooved tube 3802,as illustrated in FIG. 38E. The circular bracket 3828 and the latch base3830 may be coupled by a pin 3842 that is inserted through a firstaperture 3838 in the circular bracket, through a first pin-shiftaperture in the latch base, through a pin channel, out a second aperturein the circular bracket. A portion of the first pin-shift aperture 3846is depicted in the back perspective view of the travel limiter 3506shown in FIG. 38E. The latch 3806 may have a first ridged region 3826 onthe circular bracket 3828, and a second ridged region 3827 on the latchbase 3830. Pressing the first ridged region 3826 and the second ridgedregion 3827 towards each other may adjust the position of the circularbracket 3828 and the pin 3842 within the pin-shift apertures and pinchannel.

Some variations of a latch may comprise a mechanism that biases thelatch to a locked configuration or an unlocked configuration. Such abias mechanism enables the travel limiter to constrain the motion and/orposition of the tissue removal device without the practitionerconstantly applying pressure to the latch. One example of a biasmechanism may comprise a spring 3832 that may be located between thefirst ridged region 3826 of the circular bracket 3828 and the topportion of the latch base 3830. The spring 3832 may bias the position ofthe circular bracket 3828 and the pin 3842 with respect to the latchbase 3830. For example, the spring 3832 may bias the travel limiter to alocked configuration by pressing against the circular bracket 3828 andthe latch base 3830 such that the pin 3842 is urged to the top of thepin channel. Various latch configurations are described below.

FIGS. 38F and 38G are perspective component views that illustrate onevariation of a latch that has a locked configuration and an unlockedconfiguration. When the latch is fully assembled, the pin 3842 may beinserted from the first aperture 3838, through a first pin-shiftaperture 3846 and pin channel 2844 in the latch base 3830, to the secondaperture 3840. The circular bracket 3828 is coupled to the latch base3830 via the pin 3842, and is also held in place by the distal baseplate 3829 and the proximal base plate 3831. The latch base lumen 3836may have a diameter that is equal to, or somewhat larger than, thediameter D4 of the grooved tube body 3820. There may be a pin channelcutout 3834 that allows a segment of a pin that is inserted through thepin channel 3844 to enter the latch base lumen 3836. FIG. 38G depicts aperspective side view of the circular bracket 3828 and the latch base3830. The pin-shift aperture 3826 and the cross-section of the pinchannel 3844 may have an elongated rounded shape. The pin-shift apertureand the pin channel cross-section may be any suitable shape such thatthe bottom portion of the shape is below the bottom of the latch baselumen 3836, and the top portion of the shape is above the bottom of thelatch base lumen. For example, when the latch is in an unlockedconfiguration, a pin that is inserted through the pin channel 3844 ispositioned at the bottom of the pin channel 3844, and may be entirelyoutside the latch base lumen 3836. In the unlocked configuration, thelatch may slide freely over the grooved tube. In the locked position,the pin is positioned at the top of the pin channel, and a segment ofthe pin enters the latch base lumen 3836 via the pin channel cutout3834, which may impede the sliding of the latch 3806 over a groovedtube. In the variation of the latch 3806 described here, when in thelocked configuration, the pin may engage within one of the grooves ofthe grooved tube in the locked configuration, which may immobilize theposition of the latch along the tube. In some variations, the latch maybe biased to either the locked configuration or the unlockedconfiguration. For example, as shown in FIG. 38E, the spring 3832 biasesthe latch to the locked position by pushing upwardly on the circularbracket 3828. When the spring 3832 is compressed, the pin 3842 may bedisengaged from the groove, and urged to the bottom of the pin channel3844. This may unlock the latch 3806 and allow it to slide over thegrooved tube.

The position of the latch 3806 along the grooved tube 3802 may limit themovement range of the slide tube 3808. Where a cannula, stylet, or othertool is attached to the connector 3810 over the outer tube 3508, themovement of the slide tube determines the movement of the attached tool.Referring back to FIG. 38A, the latch 3806 is shown to be locked overthe second groove 3805. In the configuration shown there, the serratedlocking features 3816 on the slide tube are engaged with the lockingfeature mate 3818 on the grooved tube, which prevents the slide tube andthe attached tube from rotating, and also restricts axial movement. Whenthe latch 3806 is locked into the first groove 3804, the serratedlocking features 3816 may be disengaged from the locking feature mate3818, which allows the slide tube and the attached tool to rotate, aswell as to move axially.

The components and configurations of one variation of a travel limiterhave been described above. While the travel limiter 3506 has two evenlyspaced grooves, other variations may have more than two grooves, wherethe spacing between the grooves may be varied. For example, grooves maybe more closely spaced towards the distal portion of the travel limiterthan at the proximal portion of the travel limiter. The travel limiter3506 as shown has one latch 3806, however, other travel limiters mayhave two or more latches. For example, a first latch may be positionedproximal to the slide tube, while a second latch may be positioneddistal to the slide tube. These optional features may allow the travellimiter to limit either or both the axial and rotational movement of thetissue removal device with respect to slide tube. For example, when theslide tube is fixedly attached to an access cannula, the movement of thetissue removal device with respect to the slide tube may be constrainedby the latch position on the grooved tube. Any combination of the abovedescribed travel limiter components may be used to control and regulatethe position and/or orientation of the distal portion of the tissueremoval device.

Any appropriate embodiment of a handle housing may be used with thetissue removal systems described herein. For example, FIGS. 42A and 42Bdepict one example of a tissue removal system 4202, comprising an outershaft 4204 coupled distally to a tissue removal housing 4206 thatcomprises a retractable and rotatable tissue removal element 4208comprising a cable. The shaft 4204 may be coupled proximally to aproximal housing or handle housing 4210. The handle housing 4210 mayinclude an adjustment actuator 4212 and a power actuator 4214. Theadjustment actuator 4212 is configured to extend and retract the tissueremoval element 4208 of the tissue removal system 4202 and is describedin greater detail below. The power actuator 4214 depicted in FIG. 42Bcomprises an on/off switch that turns the system 4202 on and off. Inother examples, a speed actuator may be provided, such as a slider ordial to adjust the rotational speed of the system 4202. In some furtherexamples, the power actuator and the speed actuator may be incorporatedtogether, e.g. where the “off” position comprises a rotational speed ofzero. In some further examples, the speed actuator also permitsrotational speed in the opposite direction, which may facilitateunraveling of any material caught by the rotational mechanism. In stillother examples, the system 4202 may be turned on with activation of theadjustment actuator 4212. Rotation may be initiated at the beginning orend of the travel range of the adjustment actuator 4212, or anywherein-between. An internal power switch may be configured to activate atthe desired trigger position of the adjustment actuator 4212.

The handle housing 4210 in FIG. 4A may further comprise a trap cavity4216 configured to retain any fluid or particulate material transportedfrom the tissue removal housing 4206. The trap cavity 4216 may furthercomprise a cap 4218 a to permit sampling or removal of any materialstherein. The cap 4218 a may further comprise a tether 4218 b attached tothe trap cavity 4216 to avoid inadvertent loss of the cap 4218 a. Insome further variations, the trap cavity 4216 may comprise an opticallytransparent material to facilitate viewing of its contents, and mayfurther comprise a lens element 4220, depicted in FIG. 42B, located in asidewall of the trap cavity 4216 that permits magnified viewing of thecavity materials. The handle housing 4210 may further comprise one ormore ridges 4210 a, recesses or sections of textured or frictionalsurfaces, including but not limited to styrenic block copolymers orother polymer surfaces. Although not depicted in FIGS. 42A to 42C,tissue removal system 4202 may optionally comprise a travel limitermechanism, including but not limited to the travel limiter systemdepicted in FIGS. 38A to 38G.

Tissue removal assemblies, such as the variations described above, mayvary according to the geometry, consistency, location, and size of thetarget tissue. Another variation of a tissue removal assembly isillustrated in FIGS. 39A to 39C. The tissue removal assembly 3510comprises a tube stop 3912 attached distally to the outer tube 3508, arotatable drive member 3922 extending through the tube stop 3912, and acable 3910 extending from the rotatable drive member 3922 that isthreaded through a rotatable cable shaft 3900. The rotatable cable shaft3900 may comprise a distal tip 3904 with a distal channel 3908, a shaftbase 3902 with a proximal channel 3906, and a shaft body 3901 connectingthe shaft base and distal tip. The rotatable cable shaft base, body, anddistal tip may be integrally formed, or may be separately formed andassembled. The cable 3910 may be threaded from the handle 3502 throughthe rotatable drive member 3922, through the proximal channel 3906,around the rotatable cable shaft 3900, into the distal tip 3904, andattached within the distal tip 3904. The cable 3910 may have an extendedconfiguration, as shown in FIG. 39A, where at least a portion of thecable 3910 is displaced further away from the rotatable cable shaft 3900than the same portion in a retracted configuration. The cable 3910configuration may be adjusted by sliding the cable 3910 in or out of theproximal channel 3906. One or more components of the tissue removalassembly 3510 may be made of a radiopaque material. Other detailsregarding the movement of the cable between the retracted and extendedconfigurations have been described previously.

The tube stop 3912 comprises a tubular body that has a diameter that issimilar to the diameter of the outer tube 3508, and a rim 3913 that hasa diameter that may be larger than the outer tube diameter. The largerdiameter rim 3913 may help to prevent any devices that may be threadedover the outer tube 3508 near the proximal portion of the tissue removaldevice from unintentionally sliding down towards the tissue removalassembly, where it may disrupt the function of the rotating components.Optionally, portions of the tube stop 3912, such as the rim 3913, maycomprise one or more cutting edges, which may help to break up tissue asit is transported proximally by the tissue transport assembly 3920. Thetube stop 3912 tubular body may have a diameter of about 0.02 inch toabout 0.5 inch, for example, 0.05 inch, and may be made of any suitablemetallic or polymeric materials as previously described. For example,the tube stop 3912 may be made of stainless steel or a titanium alloy,and may be soldered, welded, or brazed onto the outer tube 3508.

In the variation of a tissue removal assembly described here, therotatable cable shaft 3900 is attached distal to the tube stop 3912,e.g., to the tissue transport assembly 3920. In other variations, therotatable cable shaft 3900 may be directly affixed to the tube stop3912. As seen in FIGS. 39A and 39B, the rotatable cable shaft base 3902may be attached to the rotatable drive member 3922. The shaft base 3902may be attached to the drive member 3922 by soldering, welding, brazing,heat bonding, chemical bonding, other forms of adhesive bonding, snapfitting, and the like, as described previously. While FIG. 39A depictsthat the rotatable shaft 3900 is attached to the drive member 3922distal to the tube stop 3912 and the outer tube 3508, in othervariations, the rotatable shaft may be attached to the drive member at amore proximal location, e.g., within the tube stop, within the outertube. In some variations, the rotatable cable shaft 3900 may beintegrally formed with the rotatable drive member 3922.

A rotatable cable shaft may be sized and shaped to retain the cable suchthat the cable is able to be extended, retracted, and/or rotated.Various features may be provided on a rotatable cable shaft to provideadequate attachment of the cable while dissipating and/or stabilizingforces and heat that may result from rotating the cable. These heatdissipating and force stabilization features may help prevent trauma tosurrounding tissue structures. The rotatable cable shaft 3900 maycomprise a shaft body 3901 that connects the proximal shaft base 3902and the distal tip 3904. The shaft body 3901 may have a diameter ofabout 0.010 inch to about 0.030 inch, or 0.025 inch, and a length ofabout 0.1 inch to about 0.2 inch, e.g., 0.3 inch. The shaft body 3901may be made of metallic and/or polymeric materials which may help toreduce abrasion of the cable 3910 during use, for example, materialssuch as stainless steel (17-4, 303, 304, 316, 400 series), cobaltchromium, titanium alloy, PEEK, PEBAX, nylon, polyethylene, polyimide,etc. In some variations, a shaft body may comprise protrusions, tortuousgrooves, recesses, or other surface features that may help position andstabilize a cable that is in the retracted configuration. Optionally, ashaft body may have one or more ports, channels, slots, apertures,openings, etc. for aspiration and collection of tissue and/or fluids, aswell as for the infusion of fluids or therapeutic agents. For example,there may be one or more aspiration windows on the shaft body 3901 nearthe distal tip portion 3904.

The distal tip 3904 may have an atraumatic shape, such as a blunt orrounded configuration as shown. Other atraumatic configurations havebeen described and depicted above. An atraumatic geometry may help toprevent or reduce tissue damage as the tissue removal assembly isadvanced to the target tissue region. In some variations, the distal tipmay have an angled, pointed, or tapered configuration. Theseconfigurations may help the distal tip to gain entry to tighter tissueregions, for example, between tissue folds, tubular structures, and thelike. Optionally, the distal tip may comprise multiple points or edgesthat may be used to disrupt or otherwise remove tissue or bodystructures. For example, the surface of the distal tip may comprisesurfaces with a grit that may be used as a burr mechanism. The distaltip 3904 may have a larger diameter from the shaft body 3901, forexample, the distal tip may have a diameter of about 0.025 inch to about0.040 inch, or 0.033 inch. In some variations, the distal tip may haveone or more apertures that may be used to draw tissue and/or fluids tothe tissue transport assembly, where the tissue and/or fluids may betransported proximally by the helical member 3924 mounted on therotatable drive member 3922. The distal tip 3904 may be made of metallicand/or polymeric materials that may help to reduce abrasion of the cable3910 during use, for example, materials such as PEEK, PEBAX, nylon,polyethylene, polyimide, etc.

The rotatable cable shaft 3900 may have one or more pre-formed recessesor grooves on along the cable shaft body 3901, the distal tip 3904,and/or the shaft base 3902 to receive the cable 3910, and stabilize thecable in either its extended or retracted configurations. In somevariations, pre-formed recesses or grooves along the shaft body 3901 maybe angled and positioned to reduce focal forces or stresses on the cableshaft 3900. For example, the distal channel 3908 and/or the proximalchannel 3906 may be formed at an angle with respect to the cable shaftbody 3901 to better accommodate the curvature of the cable 3910. Theangle of the distal channel 3908 and the proximal channel 3906 withrespect to the longitudinal axis of the cable shaft body may be thesimilar or different, and may be from about 5° to about 170°, e.g.,about 45° or about 135°. The distal channel 3908 and the proximalchannel 3906 may be substantially aligned along the outer surface of thecable shaft 3900, or may be in rotated positions with respect to eachother, e.g., the proximal channel 3906 may be located from about 10° toabout 359° around the cable shaft body from the location of distalchannel 3908. As depicted in FIGS. 39A-C, the distal channel 3908 may atleast partially wrap along an outer surface of the distal tip 3904before attaching at the distalmost portion of the distal tip 3904. Theremay be any number and configuration of tapered regions, tortuousgrooves, recesses, protrusions, and cable shaft surface features thataccommodate the curvature and motion of the cable 3910. Surface contoursas described above may also help prevent the cable from slipping underdynamic tension during use. The rotatable cable shaft 3900 may be madeof polymeric and/or metallic materials, including metal alloys, such asstainless steel, titanium alloys, etc.

The cable 3910 may be made of any materials similar to the materialsused for the elongate member. For example, the cable 3910 may be made ofone or more of the following metallic and/or polymeric materials:polyimide, stainless steel, titanium alloy, cobalt chromium, tungsten,polyethylene, nylon, carbon fiber, urethane, polyaramide, PEEK, and/orpolyester. The cable 3910 may also have any diameter that may beappropriate for removing tissue. For example, the cable 3910 may have adiameter of about 0.1 mm to about 0.5 mm, for example, about 0.25 mm toabout 0.35 mm, about 0.2 mm to about 0.35 mm, or may be 0.25 mm or about0.3 mm. The cable 3910 may be a multifilament cable, e.g. a metal cablesuch as a 304 stainless steel cable, or 316LVM stainless steel whereinthe cable 3910 may have a diameter that is about 2 to 12 times, e.g., 2to 4 times, or 3 times, the diameter of one filament. The filaments maybe assembled in a left hand lay orientation to form the cable. Where thecable is made of multiple polymeric filaments, the cable diameter may beabout 25 times, 50 times, or 100 times, the diameter of one polymericfilament. The filaments may be twisted around a core filament at a pitchof about 0.25 mm to about 6 mm, e.g., about 0.75 mm to about 3 mm, about0.75 mm to about 1 mm, and may be braided or woven. In some variations,the cable 3910 may be encased by a sheath that may have a tensilemodulus of about 2000 MPa to about 5000 MPa, e.g., about 2500 MPa toabout 4500 MPa, and a tensile strength greater than about 60 MPa. Thesheath may be made of polyimide and may have a thickness of about 0.075mm. The sheath may have a steel braid or coil therein, where the braidor coil filaments may be about 0.025 mm to about 0.18 mm wide, or about0.012 mm to about 0.12 mm thick, e.g., 0.1 mm thick. A cable sheathalong at least a part of the cable (and optionally, along the entirelength of the cable) may help to prevent the cable 3910 from slippingalong the rotatable cable shaft 3900, which may unintentionally changeorientation of the tissue removal assembly 3510. The cable 3910 may havesheath configurations, surface modifications and coatings,cross-sectional shapes, and material characteristics, e.g., flexuralmodulus, that are similar to the elongate members as described above.

The proximal end and the distal end of the cable 3910 may be attached tothe motor and the tissue removal assembly using any method appropriatefor the material composition of the cable and the structure to which itis attached. For example, the distal portion of a metal cable may besoldered, welded, or brazed to the distal tip 3904 of the rotatablecable shaft 3900, where the attachment may be optionally reinforced by aring, where the ring may be made of metals, e.g. stainless steel, and/orpolymers, e.g. PEEK, polyimide. The proximal portion of a metal cablemay also be similarly attached to a distal portion of the rotatabledrive member 3922, at the shaft base 3902, and/or to components in thehandle 3502, e.g., the coupler 3608, the rotatable shaft 3606, the pin3609, a slidable metal lug coupled to the pin 3609 disposed within therotatable shaft, etc. A polymeric cable may be adhesive bonded, e.g.,using epoxy, to the components described above, and may be optionallyreinforced by a metallic and/or polymeric ring.

The cable 3910 may have one or more pre-shaped curves as it wraps therotatable cable shaft 3900 from where it extends from the proximalchannel 3906 and inserts along the distal channel 3908. In somevariations, the cable may be attached in or around the distal channel atan attachment point 3905. The geometry, size, and location of thepre-shaped curves may help to define the cutting volume and geometry ofthe tissue removal assembly. Pre-shaped curves that may be used with acable in a tissue removal assembly may be flexible, where the pre-shapedcurves may be straightened when tension is applied. For example, in aretracted configuration, tension applied to the cable from a proximallocation may act to straighten the cable, so that the cable tracks alongthe surface of the rotatable cable shaft. When the tension is released,the cable may turn along the pre-shaped curve, and as the cable isfurther urged into the expanded configuration, the angle of thepre-shaped curve may become sharper. Cable materials with varyingdegrees of compliance may be used to enhance or limit the curvature ofthe cable. For example, a stiffer material may impose an upper bound oncable curvature, while a flexible material may permit the cable to flexto angles beyond the curvature of the pre-shaped curve. Examples ofpre-shaped curves are depicted in FIGS. 39A to 39C, and FIGS. 40D to40F. A first pre-shaped curve 3930 may be formed along a portion of thecable 3910, and may have a curve angle A1, where A1 may be from about30° to about 75°, and may form a peak along any desired length of thecable 3910. The cable 3910 may extend away from the cable shaft 3900towards the first pre-shaped curve 3930 at an angle A7 with respect tothe longitudinal axis of the cable shaft 3900. The cable 3910 may extendback towards the cable shaft 3900 from the first pre-shaped curve 3930at an angle A3, where the angle A3 may be different from the angle A7.The angle A7 may be substantially perpendicular to the cable shaft 3900,and/or may be from about 20° to about 110°, e.g., 85°, 90°. The angle A3may be from about 2° to about 100°, e.g., 30°, 45°. The curve 3930 maybe located centrally along the length of the cable 3910, with the anglesA7 and A3 substantially equal to each other, such that the cable may besymmetric in the expanded configuration, e.g., similar to a normalcurve. Alternatively, the curved cable 3910 may not be symmetric, e.g.,the curve 3930 may be biased towards, or located at a distal portion ofthe cable 3910, as shown in FIG. 39A. In other variations, an asymmetriccable may have curves that are biased toward, or located at a proximalportion of the cable. A second pre-shaped curve 3932 may be formed alonga portion of the cable 3910 that is distal to the first curve 3930,where it may form an angle with the cable shaft body 3901 as it crossesand wraps the shaft along the distal channel 3908. The cable 3910 maywrap a longitudinal length L10 of the cable shaft 3900, where L10 may befrom about 10% to about 50% of the length of the cable shaft 3900, e.g.,from about 0.25 mm to about 2.5 mm, e.g., 1 mm. The second curve 3932may be from about 100° to about 170°. The portion of the cable thatwraps around the shaft body 3901 and the distal tip 3904 may have alength L2 between the vertex of angle A2 and the distal attachment 3905may be from about 0.1 inch to about 0.2 inch. The length L2 may bedetermined in part by the maximum pressure that can be sustained by thedistal tip 3904 and distal attachment 3905 during cable rotation beforethe distal tip material and/or attachment fail, e.g., failure bywarping, deforming, detachment, overheating, etc. For example, extendingthe length L2 may distribute the rotational forces over a larger regionof the rotatable cable shaft 3900, which may help to reduce the failurerate of the tissue removal assembly during use. In some variations, thelength of the cable 3910 that is wrapped around and/or contacting thecable shaft 3900 may be 10%, 20%, 25%, 35%, etc. of the total length ofthe cable 3910 in the expanded configuration. For example, in theexpanded configuration, the cable 3910 may have a total length of about10 mm to about 15 mm, and in certain variations, the length of the cablethat contacts and/or wraps the cable shaft 3900 may be from about 0.1 mmto about 4 mm. The degree of turning of the cable 3910 around the cableshaft 3900 may be from about 180 degrees/turn to about 360 degrees/turn.The cable 3910 may be wrapped around the cable shaft 3900 such that itwraps from about 10° to about 540° around the circumference of the shaftbody 3901, e.g., from about 200° to about 350°, or from about 340° toabout 370°. Optionally, a third pre-shaped curve 3934 (FIG. 39B) may beformed along a portion of the cable 3910 that is proximal to the firstcurve 3930, where the third curve 3934 may be from about 100° to about170°. Another view of the pre-shaped curves of the cable 3910 in theextended configuration is depicted in FIG. 39C. The cable 3910 extendsout of the proximal channel 3906 to attain a peak displacement distal atalong the first curve 3930, then angles downward to spiral around theshaft body 3901 along the second curve 3932, crossing over and along thedistal tip surface into the distal channel 3908. In some variations, thecable may extend beyond the distal tip 3904 in either the extended orretracted configuration, for example, the cable may have an inflectionpoint that is about 0.5 mm to 5 mm, e.g., 1 mm to about 5 mm, or about 2mm away from the distal tip 3904. Extending the cable beyond the distaltip of the tissue removal assembly in the retracted configuration mayallow the cable to assume a larger profile in the extended or expandedconfiguration. The cable 3910 may have any of the characteristics, e.g.,number of turns, orientation of turns, rate of turning, inflectionpoints, pitch angles, turning lengths, etc., of the elongate membersdescribed previously. A cable may be shaped to have the curves, turns,inflection points, etc. described above by bending the cable in a tightradius during manufacturing or using a clamping device to crimp or kinkthe cable. The rotatable cable shaft 3900 may have grooves, recesses,undulations, and/or curves that accommodate the turns and curves of thecable in both the retracted and extended configurations.

In some variations of the tissue removal assembly described above, thecable exits the rotatable cable shaft from a proximal location and isattached at a location that is distal to where it exited the rotatablecable shaft. For example, the cable 3910 exits the proximal channel 3906and is attached at the distal attachment 3905 in the distal tip 3904,where the distal tip 3904 is distal to the proximal channel 3906. Inother variations of a tissue removal assembly, the cable may be attachedto the rotatable cable shaft at a location that is proximal to where itexits the shaft. This configuration may help to reduce the profile ofthe tissue removal assembly in the retracted configuration, which mayimprove the ability of the tissue removal device to access tight tissueregions, e.g., a vertebral body. Examples of the distal portion of therotatable cable shaft and the various cable configurations are depictedin FIGS. 39D-39F. For example, in FIG. 39D, the cable 3962 extendsthrough the rotatable cable shaft 3960, exits at the distal exitlocation 3967, and is attached to the proximal attachment 3966. As shownthere, the cable 3962 comprises a curved portion 3963 that coils into aloop 3964, which then extends into a straightened portion 3965 thatattaches to the rotatable cable shaft 3960 at the proximal attachment3966. The loop 3964 may be continuous and/or integral with the curvedportion 3963 and the straightened portion 3965, or it may be continuouswith curve portion 3963, and hooked to the straightened portion 3965.The distal exit location 3967 of the cable may be centered along across-section of the rotatable cable shaft 3960. FIG. 39E depicts avariation of a tissue removal assembly where the distal exit location3977 is offset with respect to a cross-section of the rotatable cableshaft 3970. As shown there, the cable 3972 exits the offset distal exit3977, and attaches to the rotatable cable shaft 3970 at a proximalattachment 3976. The cable 3972 may have a curved portion 3972 thattransitions to a straightened portion 3875 at an inflection juncture3974. The cable 3972 may also be used with a rotatable cable shaft 3978that has a beveled and/or tapered distal tip 3979, where the cable 3980may exit the rotatable cable shaft 3978 at distal exit 3980, and attachto the rotatable cable shaft 3978 at the proximal attachment 3981. Atissue removal assembly that has a cable configured with a curvedportion, an inflection juncture, and a straightened portion may help toremove tissue located at certain regions, while substantially preservingtissue at other regions. For example, in a discectomy to treatherniation or for nucleus replacement, this cable configuration may beused to cut and remove the nucleus, but generally preserve thecartilaginous endplate.

In some variations, the rotatable cable shaft may have one or more portsor windows for aspiration, infusion of therapeutic agents, and tissueand/or fluid collection. One example of a rotatable cable shaft with adistal port and at least one side window is shown in FIG. 39G. Thetissue removal assembly 3940 may comprise an inner tube 3944 that isaffixed to the distal portion of an outer tube 3950, a rotatable drivemember 3942 in outer tube and extending through the inner tube, arotatable cable shaft 3942 assembled over the inner tube 3944, and acable 3946 in the rotatable drive member 3948 that extends through theinner tube 3944, exits a distal port 3941 in the rotatable cable shaft3942, and attaches to the rotatable cable shaft at a proximal attachment3947. The rotatable cable shaft 3942 may have a rotatable cable shaftwindow 3943 and the inner tube 3944 may have a corresponding inner tubewindow 3945, where at least a portion of both windows may be aligned.Tissue may be taken through the rotatable cable shaft window 3943,through the inner tube window 3945, and transported proximally to acollector by the rotatable drive member 3948. During use, a motor mayrotate the rotatable drive member 3948, the rotatable cable shaft 3942,and the cable 3946 to cut, emulsify, and/or remove tissue. When therotatable cable shaft window 3943 and the inner shaft window 3945 areaxially aligned, e.g., in the course of rotation, the rotatable drivemember 3948 may be exposed to draw in tissue, which may then betransported to a collector. Tissue and/or fluids may also be aspired,and/or otherwise drawn in through the distal port 3941. In addition tocutting, emulsifying, etc. tissue with the rotating cable 3946, thedistal port 3941, rotatable cable shaft 3942, the inner tube 3944, therotatable drive member 3948, and other features may have sharpened edgesand the like to further cut or break up tissue that is being drawnproximally along the rotatable drive member, as described previously.

Other variations of tissue removal assemblies may have a plurality ofaspiration apertures, as depicted in FIGS. 40A-40E. Tissue removalassembly 4000 comprises a tubular member 4004 attached distally to theouter tube 4002, a rotatable drive member 4030 extending through thetubular member 4004, a rotatable cable shaft 4010 attached distally tothe rotatable drive member 4030, and an elongate member as previouslydescribed and configured. The tubular member 4004 may comprise aplurality of apertures, for example, a first aperture 4006 and a secondaperture 4008 located across from the first aperture. These aperturesmay be sized and shaped for the passage of tissue therethrough, whichmay be transported by a tissue transport assembly 4034 to a collector.For example, tissue that is removed may be transported away from thetarget tissue site via the first and second apertures 4004 and 4008. Thetubular member 4004 may be about 4 mm to about 5 mm, e.g., about 4.7 mmlong, and may have an outer diameter of about 1 mm to about 1.5 mm,e.g., about 1.4 mm, and an inner diameter of about 0.5 mm to about 1 mm,e.g., about 0.9 mm. The first and second apertures 4004 and 4008 may beshaped as ellipses, with a length of about 1.25 mm to about 1.75 mm,e.g., about 1.7 mm. The rounded ends of the ellipse-shaped apertures mayhave a radius of curvature of about 0.45 mm. Other variations ofapertures may have any suitable shapes, such as circular, rectangular,etc., and may have slotted, as appropriate for drawing tissue or fluidtherethrough. The tubular member 4004 may be made of any of the metallicand/or polymeric materials as described above, for example, it may bemade of passivated or electro-polished 17-4 stainless steel.

The rotatable shaft 4010 may comprise a distal tip 4018 with a distalchannel 4016, and a shaft base 4020 with a proximal channel 4014. Thedistal tip 4018 may have a cylindrical shape, where the distalmost tipis flattened with rounded edges. As illustrated in FIG. 40B, thediameter of the shaft base 4020 and the distal tip 4018 may be similarto the diameter of the shaft body 4012, however, in other variations,the diameter of the shaft base may be larger or smaller than thediameter of the distal tip. For example, the shaft body 4012 may have adiameter of about 0.010 inch to about 0.030 inch, or about 0.025 inch,while the distal tip 4018 and/or the shaft base 4020 may have a diameterof about 0.025 inch to about 0.040 inch, or about 0.033 inch. Therotatable shaft 4010 may have a length L4 of 0.3 inch to about 0.4 inch,for example, about 0.335 inch or about 0.353 inch. The shaft base 4020may have a length L5 of about 0.100 inch. The distal tip 4018 may have alength L7 of about 0.05 inch. The shaft base 4020 may be separated fromthe distal tip 4018 by a length L6 of about 0.20 inch. Optionally, theshaft base 4020 may have a rim that has a larger diameter than the shaftbase, which may help the rotatable shaft 4010 attached to the drivemember 4020. The rotatable shaft 4010 may be made of any of the metallicand/or polymeric materials described above, for example, it may be madeof passivated or electropolished 17-4 stainless steel.

As seen in both FIGS. 40A and 40C, the distal channel 4016 and theproximal channel 4014 may be located such that they are aligned alongthe surface of the rotatable shaft, e.g. a line between them issubstantially parallel with the longitudinal axis of the rotatable shaft4010. In other variations, the distal channel 4016 and the proximalchannel 4014 may be offset at an angle with respect to each other, e.g.,the proximal channel may be located at rotated position along thesurface of the rotatable shaft 4010, where the degree of rotation may befrom about 10° to about 359°. The distal channel 4016 and the proximalchannel 4014 may be formed at an angle with respect to the longitudinalaxis of the shaft body 4012. The angles grooves and recesses associatedwith these channels may accommodate the curves and orientation of thecable, and may help to position the cable to reduce focal forces and/orloading on the rotatable shaft 4010. For example, a distal recess 4017along the distal tip 4018 terminating at the distal channel 4016 may belocated at an angle A4 with respect to the shaft body 4012, where theangle A4 may be from about 90° to about 170°, e.g., about 135°. Theproximal channel 4014 may be formed at an angle that may be greaterthan, equal to, or less than the angle A4 of the distal recess 4017associated with the distal channel 4016. The width of the recess 4017may be determined in part by the width and/or diameter of the cable aspreviously described, and may have any width suitable for guiding acable along the surface of the rotatable shaft 4010. The distal recess4017 may curve along the surface of the rotatable shaft 4010 at anyturning rate as previously described. Optionally, there may be one ormore similar recesses along the shaft body 4012 or shaft base 4020,e.g., associated with the proximal channel 4014. FIGS. 40D to 40F depictperspective, anterior elevational, and side views of the tissue removalassembly 4000 with a cable 4050 in an expanded configuration. The cable4050 may assume any of the expanded configurations previously described,for example, the cable 4050 may be configured as depicted in FIGS. 39Ato 39C.

The shaft base 4020 may be attached distally to the tissue transportassembly 4034 by soldering, welding, adhesive bonding, or anymaterial-appropriate technique for attaching the rotatable shaft 4010 tothe tissue transport assembly. One variation of a tissue transportassembly that may be used with a tissue removal assembly is shown inFIG. 41A. The tissue transport assembly 4034 may comprise a rotatabledrive member 4030, a helical member 4032 mounted on at least a portionof the rotatable drive member 4030, and a tubular cap 4036 attached at adistal portion of the drive member 4030. The rotatable drive member 4030may be made of one or more polymeric and/or metallic materials that aresuitable for drawing tissue up proximally from the tissue removalassembly to the collector. For example, the rotatable drive member 4030may be made of stainless steel, nickel titanium alloy, carbon fiber,high density molecular weight polyethylene, and the like. The innerdiameter of the rotatable drive member 4030 may be from about 0.010 inchto about 0.020 inch, e.g., 0.015 inch. The outer diameter of therotatable drive member 4030 may be from about 0.0350 inch to about0.0450 inch, e.g., 0.0407 inch. The helical member 4032 may beintegrally formed with the rotatable drive member 4030, or may beseparately formed and attached to the drive member. The pitch P1 of thehelical member 4032 may be from about 0.010 inch to about 0.100 inch,e.g., 0.030 inch to about 0.25 inch, or about 0.060 inch to about 0.100inch, or 0.030 inch, or 0.080 inch. The pitch P1 of the helical membermay be adjusted according to the rotational speed driven by the motor,or according to the desired rate of tissue transport from the tissueremoval assembly to the collector. The helical member 4032 may be madeof materials similar to the rotatable drive member 4030, and mayoptionally include surface modifications such as friction-reducingcoatings, fluid dynamic channels, etc., which may help to transport theremoved tissue to the collector. The helical member 4032 may be righthand wound, or left hand wound, as appropriate for tissue transport. Insome examples, the helical member 4032 may be wound in the same sense asthe rotation of the drive member. The cross-section of a helical membermay have any shape that is suitable for tissue transport. While thecross-section of the helical member 4032 is circular, in othervariations, the cross-section may be triangular, rectangular, square, orovoid. In certain variations, a rotatable drive shaft may be anintegrally formed tube, e.g., a tube formed from a solid sheet ofmaterial that is not woven or braided, with the helical member coiledalong the outer surface of the tube. In other variations, the rotatabledrive shaft may be made of multiple layers of tightly wound coiledmembers, where the inner layers of the coiled members may have a firstpitch, the outer layers of the coiled members may have a second pitch.For example, the pitch of the coiled members may vary from the innermostlayer to the outermost layer, e.g., the innermost coil layer may havethe tightest pitch, and the outermost layer may have the highest pitch.In this variation, polymers or other adhesives, such as epoxy, parylene,polyurethane, and the like, may be applied in between coiled layers oras an outer coat, to secure the threads of the outermost coiled memberto the next inner coiled layer. These adhesives coatings and layers mayhelp prevent the coiled layers from separating and lifting off eachother. In general, the tissue transport assembly 4034 may comprise oneor more recesses, grooves, channels, protrusions, and the like which mayexpedite tissue transport as desired. Other characteristics of drivemembers and helical members have been described previously, and may alsobe used with the tissue transport assembly 4034.

The tubular cap 4036 may be integrally formed with the rotatable drivemember 4030, or may be separately formed and mounted onto the rotatabledrive member 4030. The distalmost portion of the tubular cap 403 mayhave one or more apertures configured to pass a cable and/or tissuetransport assembly therethrough. The tubular cap 4036 may be attached tothe rotatable drive member 4030 by soldering, welding, adhesive bonding,friction fitting, snap fitting, and the like. In some variations, thetubular cap 4036 is made of one or more polymeric materials, such aspolyethylene, nylon, carbon fiber, urethane, polyester, polyaramide,PEEK, polyimide, and other similar materials. The rotatable shaft 4010may be attached to the tubular cap 4036 by any of the suitable methodsdescribed above.

Optionally, the tissue transport assembly may also comprise a sheath(not shown) that encases at least a portion of the rotatable drivemember 4030. The sheath may be made of polymeric and/or a metalmaterials, for example, polyimide with a stainless steel braid. Thestainless steel braid may be formed using ribbon measuring about 0.0005inch by about 0.0025 inch and have a braid density of approximately 80pic. The sheath may have an inner diameter of about 0.035 inch to about0.050 inch, e.g., 0.0420 inch. The sheath may have an outer diameter ofabout 0.040 inch to about 0.055 inch, e.g., 0.048 inch. The wallthickness of the sheath may be about 0.0030 inch. In some variations,the sheath may have a length of about 10.00 inches to about 20.00inches, e.g., 12.00 inches, or 12.25 inches.

Grooves and recesses may also help to encourage any tissue or fluid tobe drawn up from the target tissue site to a proximal collector. Anotherexample of a tissue transport assembly 4100 is shown in FIG. 41B. Asseen there, the tissue transport assembly 4100 comprises a drive member4102 that is attached at its distal end to an impeller 4106, and ahelical member 4104 mounted on at a least a portion of the drive member4106. The proximal portion of the impeller 4106 may comprise a helicalcage 4108, and the distal portion may comprise an impeller cap 4110. Theimpeller cap 4110 may be made of a polymeric material such as PEEK,PEBAX, nylon, polyethylene, polyimide, and the like, and may have alength L8 of about 0.150 inch to about 0.300 inch, e.g., 0.235 inch. Theimpeller 4106 may also comprise one or more groves and/or cutoutregions, for example, slanted groove 4112 and cutout region 4114 on theimpeller cap 4110. The slanted groove 4112 and/or the cutout region 4114may be sized and shaped for passing a cable over the surface of theimpeller 4106, similar to the grooves and recesses that may be used witha rotatable shaft as previously described. In some variations, aninsulating coating may be provided on a portion of the impeller to helpreduce the risk of thermal nerve injury during the procedure.

The helical cage 4108 may be made of a metallic material such asstainless steel or polymeric material such as PEEK. Certain variationsof an impeller may comprise two more braids similar to braid 4107. Asseen in FIG. 41C, the impeller 4106 may comprise three braids that havea clockwise pitch angle of about 30° to about 60°, e.g., 35°. The braids4107 may have a rate of turning along the length L9 of the helical cage4108 of about 3 turns/inch to about 5 turns/inch, e.g., 4.5 turns/inch.The length L9 of the helical cage 4108 may be from about 0.150 inch toabout 0.300 inch, e.g., 0.230 inch. The braid 4107 may have a width fromabout 0.015 inch to about 0.030 inch, e.g., 0.028 inch. The helical cage4108 may have any number of braids, braid twist angles, or surfacestructures such as serrations, ridges, etc., that may be useful fordrawing tissue from the tissue removal assembly to the collector. Theimpeller cap 4110 may also have one or more curved, rounded, angled,tapered, etc. edges that may help to draw tissue towards the impeller.For example, the variation of an impeller 4140 shown in FIG. 41D maycomprise an impeller cap 4148 with an angled distal tip and helical cage4147. The helical cage 4147 may have a first braid 4142, a second braid4144, and a third braid 4146. One or more of the braids may haveserrations, and there may be any number of serrations on a single braid.For example, the third braid 4146 may have two serrations 4141, 4143. Inanother variation of an impeller 4150 depicted in FIG. 41E, a braid 4156may have three serrations 4151, 4153, and 4155. The braids of theimpeller 4150 may have a braid twist angle of about 40°. FIG. 41Fdepicts an impeller 4160 with three braids that have a twist angle ofabout 30°. The braid 4166 may have three serrations 4161, 4163, and4165. FIG. 41G depicts an impeller 4170 with three braids that have atwist angle of about 50°. The braid 4176 may have three serrations 4171,4173, and 4175. In other variations, such as impeller 4136 depicted inFIG. 41H, all the braids 4132, 4134, 4146 have one or more serrations,for example, three serrations 4131, 4133, 4135. The serrations may belocated on a leading edge of each braid as determined by the braid angleand direction of rotation. The serrations may help to further break upthe tissue as it is drawn proximally away from the target tissue site.Serrations may have a positive rake (e.g., from about 30° to 40°) ornegative rake and/or may be slanted at an angle, for example, the slantangle may be between about 20° to about 40°, and/or about 60° to about80°. The angle A7 between the serrations 4131, 4133, 4135 may be fromabout 80° to 150°, e.g., 105°, or 104.6°. The sharpened or pointedportion of a serration may have an angle A8, where A8 may be from about45° to 120°. The edges of the serrations 4131, 4133, 4135 may be anylength appropriate for cutting or pulverizing tissue, e.g., from about0.001 inch to about 0.004 inch, e.g., 0.002 inch. Other variations ofserrations may be larger, with edge lengths of about 0.01 inch to about0.02 inch. The two edges of a serration may have a first short edge, anda second long edge, while in other variations, the edges may be the samelength. Serrations may have a width W1 that may be from about 0.01 inchto about 0.2 inch, e.g., 0.04 inch. Some variations of serrations may beC-shaped, and/or may have other angular geometries with sharp turningedges. Other cutting features or edges may be provided along theimpeller and/or drive shaft, such as sharpened helical members,enzymatic coatings, etc. that may break up tissue and expedite itstransport to a collector.

While certain embodiments of tissue removal devices or systems have beendescribed, other embodiments of tissue removal devices or systems may beused in a tissue removal procedure. One example of an embodiment of atissue removal system is depicted in FIG. 43A. As shown there, a tissueremoval system 4302 comprises an outer shaft 4304 coupled to a handheldhousing 4306, and a tissue removal assembly 4308. Outer shaft 4304 maycomprise any suitable material or combination of materials. In somevariations, the outer shaft 4304 may be at least partially covered byone or more layers, such as a braided polyimide layer. The layer may,for example, have a length of about 2 inches to about 18 inches (e.g. 4inches, 9 inches, 12 inches, 14 inches, 15 inches), an inner diameter ofabout 0.04 inch to about 0.06 inch (e.g. 0.0495 inch), and/or an outerdiameter of about 0.045 inch to about 0.065 inch (e.g. 0.0580 inch). Incertain variations (e.g. for cervical applications), the layer may havea length of about 4 inches. In some variations (e.g. for endoscopicapplications), the layer may have a length of about 14 inches. Othersuitable layers or materials or combinations thereof may alternativelyor additionally be used. The housing 4306 contains one or morecomponents (e.g. a motor) configured to control the tissue removalassembly 4308 and other optional features of the tissue removal system4302.

FIG. 43B provides an enlarged view of region 43B of FIG. 43A (i.e., adistal portion of the tissue removal system 4302), and FIG. 43C providesa further enlarged view of the distal portion. As shown in FIGS. 43B and43C, the static outer shaft 4304 partially covers a rotating drive shaft4305. Rotating drive shaft 4305 is coupled to or integral with a helicalmember 4307 that may be used to help transport tissue during a tissueremoval procedure. Together, the rotating drive shaft and helical memberform a tissue transport assembly. Helical member 4307 may, for example,have one or more of the features described above with reference tohelical member 70 of FIG. 17. Rotating drive shaft 4305 is also coupledto a tip portion 4330 terminating at a distal head 4316. While distalhead 4316 has a specific shape and configuration, other head shapes andconfigurations are also contemplated.

Tissue removal assembly 4308 may comprise at least one elongate member4372 having a proximal section 4374 and a distal section 4376, with eachsection coupled to the tip portion 4330. More specifically, the elongatemember 4372 extends through a proximal opening 4378 in the tip portion4330, and into a distal opening 4380 in the tip portion 4330. In someembodiments, proximal opening 4378 and/or distal opening 4380 may haverounded or smooth edges. This may, for example, prevent the edges frominadvertently becoming caught on tissue during use. As shown in FIG.43B, a portion of elongate member 4372 is surrounded by an optionalprotector 4373 which may, for example, reinforce that portion of theelongate member and prevent breakage. Other variations of devices maycomprise more than one such protector, protectors that are longer orshorter, or even no protectors. While elongate member 4372 is depictedin FIGS. 43B and 43C in its extended configuration, the elongate memberalso has a retracted configuration (not shown), similar to thosepreviously described with respect to other elongate member embodiments(e.g. elongate member 202). In some embodiments, elongate member 4372may comprise a cable or a spiral wire. Other appropriate materials mayalso be used.

Referring also now to FIGS. 43D to 43J, the tissue removal system 4302further comprises a distal sheath 4332 partially covering rotating driveshaft 4305. Distal sheath 4332 may be formed of any suitable material ormaterials, including but not limited to metal alloys such as stainlesssteel (e.g. 17-4 stainless steel or a 300-series stainless steel such as304 or 316) or nickel-titanium alloys (e.g. Nitinol). Distal sheath 4332comprises a wall portion 4334 having a first aperture 4336 and a secondaperture 4337 (FIGS. 43G and 43K) opposite the first aperture. The firstand second apertures in the wall portion 4334 may, for example, enhancethe tissue removal capabilities of tissue removal system 4302. Forexample, the first and second apertures may function as lateralaspiration ports, assisting with the proximal transport of tissue fromthe target site as the tissue is being removed, up the rotating driveshaft 4305 and, for example, into a collection chamber. It should beunderstood that while the first and second apertures are depicted hereas having identical, somewhat rectangular shapes, apertures havingdifferent shapes (e.g. circular, triangular, oval, square, etc.) mayalternatively or additionally be used in a distal sheath of a tissueremoval system. Moreover, any suitable combination of aperture sizes andshapes may be employed, and any appropriate number of apertures (e.g. 1,2, 3, 4, 5 or 10) may be used in a distal sheath as well.

FIG. 43D provides a cross-sectional view of the coupling between tipportion 4330 and distal sheath 4332. As shown there, protrusions 4350and 4354 on distal sheath 4332 help to retain the tip portion 4330.FIGS. 43E and 43F similarly depict the coupling between distal sheath4332 and tip portion 4330. As shown there, the distal face 4338 ofdistal sheath 4332 has a clover-shaped opening 4340, such thataspiration ports 4342, 4344 and 4346 (as well as a fourth aspirationport that is hidden from view) are formed between the distal sheath andthe tip portion 4330. Aspiration ports 4342, 4344 and 4346 may, forexample, be configured to aspirate material, such as emulsified orpulverized nucleus fibrosus.

FIGS. 43G to 43J depict perspective, side, front and back views,respectively, of the distal sheath 4332. As shown there, the distalsheath 4332 comprises an inner surface 4348 having four protrusions4350, 4352, 4354, and 4356 extending therefrom, thereby forming theclover-shaped opening 4340. This clover-shaped opening 4340 may aid inthe retention of the tip portion 4330. For example, the shape of theopening 4340 may help to securely embed the proximal portion 4331 of thetip portion 4330 into the distal portion 4333 of the distal sheath 4332(see FIGS. 43E and 43F), thereby limiting the likelihood of the tipportion 4330 separating from the distal sheath 4332 during use. At thesame time, the tip portion 4330 may be allowed to continue to rotatefreely, in conjunction with the rotation of the rotating drive shaft4305. In some cases in which the tip portion 4330 is less flexible thanthe rotating drive shaft 4305, the coupling between the distal sheath4332 and the tip portion 4330 may provide reinforcement to facilitatethe transition from the relatively flexible drive shaft to therelatively rigid tip portion to limit breakage.

Referring again to FIG. 43I, distal sheath 4332 has an outer diameter4444 and an inner diameter 4446. In some embodiments, outer diameter4444 may be from about 0.040 inch to about 0.180 inch, and/or innerdiameter 4446 may be from about 0.020 inch to about 0.176 inch.Additionally, in certain embodiments, and referring now to FIG. 43H,distal sheath 4332 may have a length 4329 of about 0.15 inch to about0.25 inch (e.g. 0.185 inch).

While opening 4340 has been described as clover-shaped, otherembodiments of tissue removal systems may comprise distal sheaths havingdifferent types of tip portion-retaining features, such as differentlysized and/or shaped openings. As an example, a distal sheath may have anopening with more or fewer protrusions, multiple different types ofprotrusions (e.g. protrusions having different shapes and/or sizes), orno protrusions at all. For example, in some cases, protrusions may haverounded shapes, shapes with triangular cross-sections, irregular shapes,etc. Moreover, any or all of these features may alternatively oradditionally be located further within a distal sheath. In someembodiments, other distal sheath retention features may be used, eitheras an alternative to, or in addition to, one or more protrusions. Incertain embodiments, a distal sheath may have a high-friction innersurface that can help grip onto a tip portion, or may comprise multiplesets of protrusions, such as different sets of protrusions along itslength. Additionally, in certain embodiments a tip portion may compriseone or more features that enhance the retention of the tip portion by adistal sheath of a tissue removal device. As an example, tip portion4330 comprises a ring 4994 that is depicted in FIG. 43D and that mayhelp with retention. In some cases, both the tip portion and the distalsheath may comprise retention features, while in other cases only one ofthe tip portion or the distal sheath may comprise one or more retentionfeatures. In certain variations, the tip portion may have protrusionsthat are configured to couple with grooves in the distal sheath whilestill allowing for rotation of the tip portion, or vice versa. Othersuitable couplings between a tip portion and a distal sheath may beused, including, for example, snap-lock couplings, friction fitcouplings, and the like.

Tip portion 4330 is depicted in further detail in FIGS. 43Q and 43R. Asshown there, the tip portion 4330 comprises a proximal portion 4331 anda distal portion 4335, which comprises the distal head 4316.Additionally, proximal and distal openings 4378 and 4380 are shown. Asshown in FIG. 43R, tip portion 4330 has a length 4370 which can be, forexample, from about 0.3 inch to about 0.45 inch (e.g. 0.381 inch). Thelength of the tip portion 4330 may in some cases be selected based onthe characteristics of the target site being treated. For example, alonger tip portion may be more appropriate for a larger target site thana smaller tip portion. As shown in FIGS. 43Q and 43R, the tip portion4330 has a variable cross-sectional diameter—i.e. its proximal portion4331 and distal portion 4335 have larger cross-sectional diameters thanits intermediate portion 4390. In the variation shown, the intermediateportion 4390 of tip portion 4330 has a cross-sectional diameter 4391that is smaller than the cross-sectional diameters 4392, 4393 and 4394of the proximal portion 4331, as well as the cross-sectional diameter4395 of the distal portion 4335. In some embodiments, cross-sectionaldiameter 4391 may be from about 15% to about 90% (e.g. 42%) smaller thancross-sectional diameter 4392, from about 10% to about 85% (e.g. 31%)smaller than cross-sectional diameter 4393, from about 5% to about 80%(e.g. 22%) smaller than cross-sectional diameter 4394, and/or from about5% to about 80% (e.g. 22%) smaller than cross-sectional diameter 4395.In certain embodiments, cross-sectional diameter 4391 may be from about0.015 inch to about 0.150 inch, cross-sectional diameter 4392 may befrom about 0.025 inch to about 0.175 inch, cross-sectional diameter 4393may be from about 0.020 inch to about 0.170 inch, cross-sectionaldiameter 4394 may be from about 0.020 inch to about 0.170 inch, and/orcross-sectional diameter 4395 may be from about 0.020 inch to about0.170 inch. Alternatively or additionally, the length 4385 of theproximal portion 4331 may be from about 0.1 inch to about 0.15 inch(e.g. 0.125 inch), the length 4383 of the intermediate portion 4390 maybe from about 0.15 inch to about 0.25 inch (e.g. 0.191 inch), and/or thelength 4381 of the distal portion 4335 may be from about 0.03 inch toabout 0.08 inch (e.g. 0.051 inch). These dimensions may be selectedbased on any of a number of factors, such as the desired flexibility ofthe tip portion 4330 along its length. Tip portion 4330 may comprise anysuitable material or combination thereof, including but not limited tostainless steel (e.g. 17-4 PH stainless steel, a 300-series stainlesssteel such as 304 or 316).

Referring again to FIGS. 43B and 43C, as well as to FIGS. 43K and 43L,tissue removal system 4302 also comprises an annular stop member 4360positioned circumferentially around tip portion 4330, distal to distalsheath 4332. In some cases, during use, drive shaft 4305 may moveproximally. The presence of annular stop member 4360 may prevent theoccurrence of substantial proximal movement by the drive shaft 4305.Typically, if the drive shaft 4305 starts to move proximally, theannular stop member 4360 may come into contact with the distal face 4338of the distal sheath 4332, thereby limiting or preventing any furtherproximal movement by the drive shaft 4305. Annular stop member 4360 maycomprise any appropriate material or materials, such as metals and/ormetal alloys (e.g. stainless steel).

FIGS. 43M, 43N, 430 and 43P depict side perspective, front, back andside views, respectively, of the annular stop member 4360. As shownthere, the annular stop member 4360 has a flat side 4362 and a beveledside 4364. Additionally, the annular stop member 4360 has an outerdiameter 4366 and an inner diameter 4368. In some embodiments, outerdiameter 4366 may be from about 0.04 inch to about 0.06 inch (e.g. 0.050inch). Alternatively or additionally, inner diameter 4368 may be fromabout 0.02 inch to about 0.05 inch (e.g. 0.033 inch). FIG. 43P depictsadditional dimensions of annular stop member 4360. In some embodiments,dimension 4388 may be from about 0.005 inch to about 0.015 inch (e.g.0.010 inch), and/or dimension 4389 may be from about 0.003 inch to about0.012 inch (e.g. 0.006 inch). Alternatively or additionally, angle 4387may be from about 35° to about 55° (e.g. 45°).

Of course, while an annular stop member is shown, any suitable stopmember, stop feature, or combination of stop members and/or stopfeatures may be employed on a tissue removal device. For example,non-beveled annular members, multiple annular members, angular members,projections, hooks, textured surfaces, and/or any other appropriatefeature or combination of features may be used. Additionally, stopmembers may or may not be circumferentially disposed around a device.Stop members, such as annular stop member 4360, may be integral with atip portion or other component of a tissue removal device, or may beseparately formed from the tip member or other component, and latercoupled (e.g., bonded) thereto. In some cases, a stop member may bemachined onto a tip portion or other component of a tissue removaldevice.

Referring now to FIGS. 43S and 43T, an alternative exemplary tissueassembly 4308A is depicted. Tissue assembly 4308A is similar to assembly4308, however includes an alternative stop member 4360A positionedcircumferentially around tip portion 4330, distal to distal sheath 4332.As depicted, a portion 4361 of the stop member 4360A extends distallyalong the tip portion 4330, opposite to proximal opening 4370, providingadded mechanical support. The length of portion 4361 of stop member4360A may be any suitable length to provide the desired support to theproximal portion of tip portion 4330, for example, adjacent to andconsistent with the proximal opening 4378. Alternatively, portion 4361of stop member 4360A may extend a distance along the tip portion 4330which is more or less than the length corresponding to the proximalopening 4378. As discussed with respect to stop member 4360, stop member4360A may limit or prevent proximal movement of the driveshaft 4305,while providing additional mechanical support. Annular stop member 4360Amay comprise any appropriate material or materials, such as metalsand/or metal alloys (e.g. stainless steel). Such additional mechanicalsupport may be desirable when using an alternative elongate member 4372Amade of tungsten, for example, which may be well suited for tissueremoval but may also result in increased mechanical stress to tipportion 4330.

Now referring also to FIG. 43U, the distal portion of the alternativeelongate member 4372A is depicted secured in the distal head 4316 of thetip portion 4330, tip portion 4330 shown in cross-section for clarity.The elongate member 4372A terminates in a tip 4372T, which may or maynot be trimmed flush with the distal head 4316 of the tip portion 4330.A ring 4373 is crimped, or otherwise fixedly attached, to a distalportion of the elongate member 4372A. The ring 4373 may be made from anysuitable biocompatible material, such as stainless steel or a titaniumalloy. The ring 4373 may be soldered, welded, or brazed to the distalhead 4316, thus fixedly attaching the distal portion of the elongatemember 4372A to the distal head 4316 of the tip portion 4330. Thus,while the elongate member 4372A may be fabricated from one or morematerials which resist soldering, welding, or brazing, such as tungstenfor example, ring 4373 may enable such attachment.

The tissue removal systems and devices depicted in FIGS. 21A to 22, and35A to 43R may be used for any of a variety of tissue removalprocedures, including discectomy and vertebroplasty. For example,referring to FIGS. 24A and to 24C, a vertebral body 730 may be accessedby any of a variety of access procedures described herein. As anexample, the tissue removal system 700 may be used to remove vertebraltissue and apply bone cement to the vertebral body 730. The shaft 718(not drawn to scale) may be inserted into the interior of the vertebralbody (FIG. 24A) and then rotated with the cable 702 extended to form acavity 732 in the vertebral body 730 (FIG. 24B). The tissue removalsystem 700 may be further manipulated until adequate removal ofcancellous bone is achieved. As shown in FIG. 24C, the tissue removalsystem 700 may be loaded with a bone cement 734 which is then deliveredto the cavity 732. In some examples, the bone cement 734 may comprise amaterial such as polymethyl methacrylate hydroxyapatite, or any of avariety of other bone cements or other hardenable or curable substancescan be injected through the trocar to fill the cavity created by the bythe tissue removal system 700. The cable 702 of the tissue removalsystem 700 may be retracted or extended during delivery of therapeuticagents. In some instances, the extended cable 702 may redistribute thetherapeutic agents against the cavity walls, which may reduce the riskof leakage out of the cavity.

In some of the procedures described above, the cavity in the vertebralbody is formed before the delivery of therapeutic agents, but in otherprocedures, the delivery of therapeutic agents may occur simultaneously.In procedure where the cavity is first formed, filling of the emptycavity may reduce initial filling pressures. In some instances, lowerfilling pressures may reduce the risk of leakage. In some examples, thetissue removal system may comprise a pressure sensor which may be usedby the user or may be configured automatically to shut off delivery orpressurization of the therapeutic agents upon reaching a particularpressure limit.

Although some of the examples described herein are directed to treatmentof vertebral disc fractures, in other examples, the tissue removalsystems may be used to treat or diagnose bone lesions located in thevertebrae or other bones of the body. Diagnosis of bone lesions mayinclude biopsy of bone. These bone lesions may include but are notlimited to potentially cancerous bone lesions, including osteomas,osteosarcomas and metastatic lesions, as well as potentially infectiousbone lesions, including tuberculosis. Bone cement, with or without othertherapeutic agents such as anti-neoplastic and anti-infective agents,may or may not be injected into the cavity.

The procedures described herein may target vertebral tissue in differentlocations, and as such, access sites and pathways may vary accordingly.The tissue removal devices described above may be used with one or moreaccess devices which may help direct the tissue removal device to thetarget tissue site. An access device, such as a cannula, may bepositioned with different angles of entry depending on the location ofthe targeted vertebral tissue. The range of suitable entry angles may beat least partially constrained by the location of spinal structures withrespect to the skin surface. For example, a straight cannula asdescribed above may be positioned within the range of suitable entryangles to create a linear access pathway that extends from an accesssite on the skin surface to a targeted region of spinal tissue that isco-linear with access site. A curved cannula may be used to create acurved pathway to access tissue that may not be co-linear with an accesssite within a suitable entry angle range. While a curved pathway mayprovide increased accessibility to vertebral tissue, a practitioner mayneed to undergo additional training and practice to avoid disruptingsensitive anatomical structures along a curved pathway. Some variationsof access devices may comprise a bendable flexible curvable cannula,which may have a straight configuration and a curved configuration. Thecannula may be used in the straight configuration to create asubstantially linear access pathway from the access site on the skinsurface to the vicinity of the target vertebral tissue. Once the initialaccess pathway is created, the cannula may be used in the curvedconfiguration to contact the target tissue.

In some variations, the curvature of a cannula may be determined in partby the curvature of a stylet inserted therethrough. For example,inserting a stylet with one or more curves into a bendable flexiblecannula may cause the cannula to have corresponding curves. In somevariations, a bendable cannula may have one or more pre-formed curvesthat may be straightened by inserting a straight stylet therethrough.Alternatively, a bendable cannula that is substantially straight may becurved by inserting a curved stylet therethrough. The insertion ofvarious stylets through a bendable cannula may allow a practitioner toaccess spinal tissue at different locations via one access site on theskin. This may reduce the need for withdrawing the cannula from the bodyand re-entering the body via an additional access site to access adifferent tissue region. For example, the cannula and the stylet mayeach have one or more corresponding curves such that when the stylet isinserted through the cannula, the corresponding curves may be aligned.This may act to stiffen or reinforce the curvature of the cannula sothat it may be more easily moved from a first tissue location to asecond tissue location. For example, a procedure performed on one tissuelocation in the disc annulus may be repeated at another tissue locationwithout removing the curved cannula from the disc annulus. While at thefirst tissue location, a curved or straight stylet may be reintroducedinto the cannula, which may facilitate adjustment and positioning of thecannula to a second tissue location. Insertion of a straight stylet maystraighten the curved portion of the cannula and allow thecannula-stylet assembly to be advanced to a target site that isrelatively further away from the site that has been treated. In otherembodiments where relatively insignificant cannula repositioning isinvolved, a curved stylet may be used to acquire access to a secondtarget site within the disc. A straightened and/or stiffenedcannula-stylet assembly may offer enhanced responsiveness andmaneuverability and therefore facilitate the maneuvering of the cannulawithin the discal area, and may facilitate safe removal of the devicesfrom a patient.

The length of a stylet may be greater than, or substantially equal tothe length of a corresponding cannula. For example, the distal portionof a stylet inserted into a cannula may extend or protrude from thedistal portion of the cannula, and/or may be flush with the distalportion of the cannula, and/or may even be withdrawn into the cannula,as desirable. Similarly, the tissue removal assembly of a tissue removaldevice may be extended from and/or withdrawn into the distal portion ofthe cannula. The relative longitudinal position between a cannula andstylet, and/or cannula and a travel limiter of a tissue removal devicemay be adjusted and/or locked. In some variations, the orientation ofone or more curves in a cannula and a stylet with respect to each othermay be adjusted by rotating the stylet, and may optionally be lockedonce the desired orientation is obtained. The cannula and stylet mayeach comprise complementary proximal connectors, which may be used tocouple them together, such that they may be advanced and navigatedtogether. Optionally, the proximal connectors may rotatably and/orlongitudinally lock the cannula and stylet with respect to each other.

Some variations of a cannula and/or stylet may have an orientationindicator, which may help a practitioner to identify the orientation ofthe one or more curves of the devices, or the orientation of one or moresharpened edges of a stylet, after they have been inserted into the bodyof a patient. For example, the orientation of a distal curve of acannula with respect to the longitudinal axis of the cannula shaft maybe evident by observing the configuration of the orientation indicator.Orientation indicators may also help a practitioner align the curvatureof a stylet to correspond with the curvature of the cannula that it isinserted through. In this way, the practitioner may proximally adjustthe bend orientation of the stylet, thereby allowing the stylet to passthrough the cannula bend with ease. The shape of the orientationindicator may convey the orientation of the one or more curves of thecannula and/or style to the practitioner. For example, the orientationindicator may have a shape with one or more tapered regions, where theplane of a taper is indicative of the plane of a distal curve. In somevariations, orientation indicators may have multiple apices that arealigned with multiple curves in multiple planes, which may help thepractitioner position and orient the distal portion of the tissueremoval device as desired. The orientation indicator may be attached tothe cannula and/or stylet by soldering, welding, adhesive bonding (e.g.,3311 UV adhesive that may be UV cured), snap fit, or other appropriatemethods. In some variations, the orientation indicator may be attachedor integrally formed with a proximal connector of the cannula and/orstylet. This may provide a mechanism for the cannula and stylet to becoupled together in a particular orientation.

Cannula and stylets may each have proximal connectors that couple themto each other. The proximal connector of a cannula may also be used tocouple it with a tissue removal device, e.g., a collector port and/ortravel limiter. Connectors may be any standardized connector (e.g., anyluer-type connectors, screw-type connectors, taper ground joints, etc.),or may be a proprietary connector. In some variations, a cannula mayhave a male-type connector that is configured to connect with a styletor tissue removal device with a female-type connector. Engagement of theproximal connectors of cannula, stylets, and/or tissue removal devicesmay prevent relative movement between the devices. In some variations,when a stylet is connected to a cannula, the stylet may not be able tomove longitudinally within the cannula, but may be axially rotatedwithin the cannula. This may allow a practitioner to adjust thealignment between the cannula and stylet during the insertion of thecannula and stylet into the body. Alternatively or additionally,engagement of the proximal connectors between a cannula and stylet, or acannula and a travel limiter of a tissue removal device may preventrelative longitudinal and axial motion between the devices. Locking theorientation and position between the cannula and stylet (and/or cannulaand travel limiter) may help prevent inadvertent device misalignment ormovement during a procedure.

In some examples, the distal region of the cannula and/or stylet maycomprise a radio-opaque structure (e.g. rings or bands) to facilitateconfirmation of its position using radiographic imaging. In otherexamples a separate radiographic marker instrument may be used toconfirm and evaluate the cannula placement. In one embodimentillustrated in FIGS. 27A to 27E, the radiographic marker 2700 comprisesan elongate shaft 2710 with a piece of wire 2720 (e.g., multifilament orsolid) distally attached thereto. The wire 2720 may comprise a retractedconfiguration and a deployed or extended configuration. As illustratedin FIG. 27A, when the wire is placed in its retracted configuration, itis disposed about the distal end of the marker shaft 2710 such that theplacement and/or longitudinal movement of the marker within a cannulawill not be obstructed or otherwise interfered with. As illustrated inFIG. 27B to 27E, when the wire 2720 is placed in its deployed orextended configuration, the wire 2720 may comprise a radial and a distalexcursion at the distal end of the marker shaft 2710. The deployed orextended wire comprise any suitable geometric configuration, includingbut not limited to a semi-circle (e.g., FIG. 27B), a portion of a circle(e.g., FIGS. 27C and 27D), or an ellipse (e.g., FIG. 27E), or any otherlinear, non-linear or angled shape. The radial displacement 2722 of theextended wire with respect to the central axis of the marker shaft 2710may be of about 0.07 inch to about 0.25 inch or more, sometimes about0.1 inch to about 0.2 inch, and other times about 0.15 inch to about0.18 inch. The distal displacement 2724 of the extended wire withrespect to the distal end of the marker shaft 2710 may be of about 0.07inch to about 0.25 inch or more, sometimes about 0.1 inch to about 0.2inch, and other times about 0.15 inch to about 0.18 inch. In someembodiments, other types of expandable structures, such as a balloon,may be used in the radiographic marker.

In some embodiments, the distal end of the shaft 2710 may be round orotherwise blunt to reduce tissue disruption during the insertion of themarker and the deployment of the wire. Both the distal end of the markershaft 2710 and the distal wire 2720 may be radiopaque to allowobservation under fluoroscopy or other types of imaging guidance. Theradiographic marker 2700 may also comprise a complimentary proximalconnector that locks the marker to the cannula. The radiographic marker2700 may also comprise an indicator that shows the orientation of thedeployed wire with respect to the central axis of the marker draft 2710.The radiographic marker may be inserted into the cannula with the distalwire in its retracted configuration. Once the distal end of the shaft2710 reaches the distal end of the cannula, the wire may be deployed toeither identify relevant structures within or near the visualizationzone, which is defined by the deployed wire, or to evaluate theplacement of the cannula. In some embodiments, the cannula may berepositioned to facilitate better target site access.

Examples and variations of bendable cannula and stylets are describedhere. Variations of cannula and stylets may have any combination of theabove-described features, such as connectors, orientation indicators,radio-opaque markers, etc., as appropriate.

As described previously, access to the spine for various spinalprocedures may be achieved using a cannula containing an obturator witha sharpened end. Access to the spine may also be obtained using acannula and stylet. FIG. 25A schematically illustrates a cannula-styletassembly 2500 comprising a cannula 2510 and a removable stylet 2520through a lumen of the cannula. The cannula 2510 may have one or morelumens configured to receive a stylet 2520. A proximal connector 2530 ofthe cannula 2510 and a proximal connector 2533 of the stylet 2520 mayreleasably couple the cannula 2510 to the stylet 2520. While the cannula2510 has a straight configuration, other variations may comprise one ormore curved regions. The distal end 2512 of the cannula 2510 may beround or blunt, and/or may have a rounded edge, which may reduceinadvertent damage to surrounding tissues when the assembly 2500 isadvanced to a target site. The cannula 2510 may comprise an optionalproximal connector 2530, where the connector may be a standardized orproprietary connector as previously described. In some embodiments, thestylet 2520 may comprise a lumen for guidewire to facilitate theplacement of the stylet in a patient's body.

The straight cannula 2510 may have a length from the distal portion ofthe proximal connector 2530 to the distal portion of the cannula 2531 ofabout 4 inches to about 12 inches or more, sometimes about 5 inches toabout 10 inches, and other times about 6 inches to about 9 inches. Theouter diameter of the straight cannula 2510 may be about 0.05 inch toabout 0.08 inch or more, sometimes about 0.06 inch to about 0.07 inch,and other times about 0.064 inch to about 0.066 inch. The inner diameterof the cannula 2510 (e.g., the diameter of the cannula lumen to receivethe stylet 2520) may be about 0.04 inch to about 0.07 inch or more,sometimes about 0.05 inch to about 0.06 inch, and other times about0.055 inch to about 0.057 inch. The straight cannula 2510 may be madefrom any type of rigid or semi-rigid materials, such as metals or metalalloys (e.g., stainless steel, including but not limited to cold-worked304/416 stainless steel, full hard 17-4 stainless steel, and 400 seriesstainless steel, nickel titanium alloys, etc.). The proximal connector2530 of the cannula may be made from metal or plastic materials.

The straight stylet 2510 may comprise an elongate shaft 2521 and adistal tip 2522, which may extend distally from the cannula distalportion 2531. The straight stylet 2520 may be used to penetrate, cut,dissect, or otherwise disrupt tissues/bones, thereby forming apassageway or a working channel to a target site. The distal tip 2522 ofthe stylet may be sharpened, and may optionally comprise a beveled edge2524, as illustrated in FIG. 25B. In some embodiments, the bevel may beabout 10° to about 45°, sometimes about 20° to about 30°, and othertimes about 23° to about 26°. In some variations, the distal tip 2522may have a plurality of beveled edges, e.g., two, three, four or moreedges.

The distal tip 2522 may have a variety of shapes and geometries. Forexample, the distal tip may have a frusto-conical configuration 2532(e.g., FIG. 25C) or a conical configuration 2542 (e.g., FIG. 25D). Inother embodiments, the stylet tip 2552 may be round (e.g., FIG. 25E). Insome examples, a round or blunt tip may reduce inadvertent damage tosurrounding tissues when the stylet is extended from the cannula, or mayfacilitate blunt dissection along tissue planes.

The length of a straight stylet from the distal portion of a proximalconnector 2533 to distal tip 2522 of the stylet may be the same as, orsomewhat longer than, the length of a cannula. A stylet may have alength of about 4 inches to about 12 inches or more, for example, fromabout 4.01 inches to about 12.01 inches, or about 6.01 inches to about9.01 inches. In some variations, the stylet may be substantially longerthan the cannula, such that when the stylet is inserted into the cannulaand coupled via the proximal connectors (2530, 2533), the distal tip2522 of the stylet extends distally from the cannula distal portion2531. The stylet may extend about 0.05 inch to about 0.5 inch from thedistal end of the cannula, and may even extend more than 1 inch from thecannula, for example, 1.5 inches or 3 inches. In this way, the styletand the cannula are advanced together to a target area as an assembly.In some embodiments where the stylet 2520 comprises a beveled distal tip2524, the entire beveled edge 2524 of the stylet 2520 may be exposeddistally with respect to the distal end 2512 of the cannula 2510 (asillustrated in FIG. 25B). In other embodiments, when the stylet 2520 isproximally coupled to the cannula 2510, only a portion of the bevelededge 2524 is exposed. The outer diameter of the straight stylet may besuch that it can be slidably inserted through the cannula, and may bethe same as, or less than, the inner diameter of the cannula. Forexample, the outer diameter for the straight stylet may be about 0.03inch to about 0.067 inch, sometimes about 0.05 inch to about 0.06 inch,and other times about 0.05 inch to about 0.054 inches. The straightstylet may be made of a rigid or semi-rigid material similar to that ofthe straight cannula, such as stainless steel, etc. The distal tipand/or the shaft of the stylet may be radiopaque to facilitate theplacement of the stylet inside the cannula.

In some embodiments, the stylet 2520 may comprise a proximal orientationindicator, where the position and orientation of the orientationindicator corresponds with the orientation of the one or more bevelededges of the distal tip with respect to the central axis of the stylet2520. In one embodiment, the orientation indicator may be a marker onthe shaft 2521 and/or proximal connector 2533 of the stylet near itsproximal end. In another embodiment, the shaft 2521 and/or proximalconnector 2533 of the stylet may comprise a protrusion or a groove thatindicates the orientation of the bevel. The practitioner may determinethe orientation of the stylet bevel by observing the position of theprotrusion or groove on the shaft and/or proximal connector. In otherembodiments, any other suitable indicating mechanism known to theordinarily skilled in the art may be used to show the orientation of thestylet bevel.

In some procedures, a straight access may involve a longer insertiondistance in order to achieve the desired approach angle to the targetsite, and/or to avoid interference from some anatomical structures. Forexample, as illustrated in FIG. 26B, in order to have direct access to aherniated area 2640 in a vertebral disc 2641 through disc annulus 2630,the straight cannula-stylet assembly 2600 may have to enter from anentry point that is further away from the midline 2644 of the patient'sback in order to avoid the transverse spinal processes 2642. As aresult, such straight access to the herniated disc 2641 may involvelonger insertion path and therefore, may cause higher degree of tissuedisruption. In addition, because the straight assembly 2600 only offerslinear access into the discal area, if there are multiple herniatedspots in the disc and the spots are not disposed along a linear path,the assembly 2600 may need to be removed and reinserted in order totreat all spots. As a result, in some procedures, a curved access may bedesirable to provide a shorter insertion pathway and/or to reach certaintarget sites (e.g., intra-discal area) that are difficult to reach by astraight access.

In some embodiments, a bendable flexible curved cannula may be used inassociation with either a straight stylet or a curved stylet to obtaincurved access to a spinal area. A curved access pathway not only offersa larger tissue removal zone at one target site, but it may also provideflexible access to multiple target sites in one or more herniated discs.A curved or non-linear access pathway that may be provided by a bendableflexible curved cannula may be shorter than a straight access pathway,and may be less disruptive to surround tissue structures. It may alsoprovide better orientation towards the middle of a disc, as comparedwith a straight access pathway.

FIGS. 29A to 29C schematically illustrate an assembly 2900 of a curvedcannula 2910 and a straight stylet 2920 that may be used to adjust thecurvature of the cannula 2910, e.g., straighten a curved portion of thecannula. As illustrated in FIG. 29A, the curved cannula 2910 maycomprise a straight proximal portion 2912 and a curved distal portion2914. In some embodiments, the curved distal portion 2914 of the curvedcannula 2910 may be pre-shaped. The cannula 2910 may be made from aflexible or semi-flexible material such that the insertion of a straightstylet 2920 into the curved cannula 2910 may straighten the curveddistal portion 2914 to some degree if not completely straightened, asillustrated in FIG. 29B. In some embodiments, the curved cannula 2910may be made from a shape memory material. The cannula 2910 may bestraightened when a straight stylet 2920 is inserted but it maysubstantially regain its curved configuration when the stylet isremoved, as illustrated in FIG. 29C. Non-limiting examples of suitablecannula materials include shape memory metal alloys (e.g.,nickel-titanium alloy) and shape memory polymers. In some variations,the shape memory metal alloy may have an austenitic finish temperaturethat allows the curved cannula to accommodate the insertion of astraight stylet at temperatures between 65° F. and 100° F. withoutfailing, while remaining sufficiently rigid at those temperatures tomaintain the curve. Examples of appropriate austenitic finishtemperature may be from about 15° F. to about 25° F. Optionally, thesurfaces of either a straight or curved cannula may be modified with acoating, such as a silver finish, to reduce oxidation, and/or reducefrictional forces, as well as galling effects that may result from anyrotational or axial motion from a tissue removal device inserted throughthe cannula. In some embodiments, the curved distal portion 2914 maycomprise a plurality of slots 2916, or other types of recessedstructures, either equally or unequally spaced along the longitudinallength of the cannula 2910. These structures may enhance the bendingcharacteristics and/or facilitate redistribution of any compressingforce, thereby reducing damage to the distal curved portion 2914 causedby repeated bending and straightening.

The bending range of the curved cannula may be in the range of fromabout 10 degrees to about 80 degrees, sometimes from about 20 degrees toabout 70 degrees, and other times from about 30 degrees to about 60degrees, and still other times from about 40 degrees to about 50degrees. The curved distal portion 2914 may comprise a radius ofcurvature of about 0.5 centimeters to about 30 centimeters; sometimesabout 1 centimeter to about 20 centimeters, sometimes about 5centimeters to about 15 centimeters and other times about 8 centimetersto about 10 centimeters. When the curved distal portion is straightened,the curved cannula may comprise a length of about 4 inches to about 12inches or more, sometimes about 5 inches to about 10 inches, and othertimes about 6 inches to about 9 inches. The ratio between the length ofthe curved distal portion (when straightened) 2914 to the length of thestraight proximal portion 2912 may be about 0.1 to about 0.9; sometimesabout 0.2 to about 0.8; other times about 0.4 to 0.6. The outer diameterof the curved cannula may be about 0.05 inch to about 0.08 inch or more,sometimes about 0.06 inch to about 0.07 inch, and other times about0.063 inch to about 0.065 inch. The inner diameter of the curved cannula(e.g., the diameter of the curved cannula 2910 lumen to receive thestylet 2920) may be about 0.04 inch to about 0.07 inch or more,sometimes about 0.05 inch to about 0.06 inch, and other times about0.055 inch to about 0.057 inch. In some embodiments, when used inconjunction with stylets of the same size, a curved cannula may comprisea slightly larger inner diameter than a straight cannula because thestylet may need more room to navigate inside the curved cannula in orderto avoid damaging the inner surface of the curved cannula. In someembodiments, the stylet 2920 may comprise a non-beveled or otherwiseblunt distal tip to reduce the risk of damaging the interior of thecannula 2910. In some embodiments, the curved cannula 2910 and thestraight stylet 2920 may be proximally connected by complementaryconnectors, such as those previously described. The distance between thedistalmost end 2922 of the stylet 2920 and the distalmost end 2918 ofthe cannula 2910 may be in the range of about 0.02 inch to about 0.4inch, sometimes about 0.04 inch to about 0.3 inch, and other times about0.07 inch to about 0.2 inch.

In some variations, a straight stylet that may be used with a curvedcannula may have a bendable and/or deflectable region, as shown in FIG.34A. The bendable deflectable region of the straight stylet mayfacilitate the movement of the stylet through a curved cannula withoutdamaging it, while providing sufficient rigidity to straighten a curvedcannula. Stylet 3400 has a proximal connector 3406 and an elongated body3408 extending therefrom. The elongate body 3408 comprises a distal tip3402 and a deflectable region 3404, where the deflectable region 3404may be located proximal to the distal tip 3402. The deflectable region3404 may provide some additional flexibility to a distal portion of thestylet 3400. The deflectable region 3404 is configured to bend, flex,conform, and/or deflect according to the curvature of a cannula. Thedistal tip 3402, the elongate body 3408, and the deformable region 3404may be made of the same material, such as passivated 304 stainless steel(drawn hard temper) or Nitinol, and may be radiopaque underfluorescence. Alternatively, the elongate body 3408 may be made of 20 GaFEP heat shrink tubing. In some variations, the deflectable region 3404may be made of a material with an elastic modulus that is more flexiblethan the elongate body material, for example, silicone, nylon, PEEK,PEBAX, or polyethylene. Alternatively or additionally, the deflectableregion 3404 may be thinner than the elongate body (3408), and may betapered or attenuated from the elongate body, i.e., the deflectableregion may have a diameter that is smaller, or more narrow, than theother regions of the elongated body. The elongate body 3408 may have andiameter of about 0.030 inch to about 0.060 inch, e.g., 0.039 inch or0.045 inch or 0.060 inch, and may have a wall thickness of about 0.004inch to about 0.010 inch, e.g., 0.008 inch. The length of the elongatebody 3408 may vary from about 6 inches to about 9 inches, e.g., 8inches.

As described previously, the outer diameter of a stylet may be about0.04 inch to about 0.07 inch or more, e.g., 0.054 inch, while thedeflectable region 3404 may be from about 0.015 inch to about 0.035inch, for example, 0.023 inch. In some variations, the diameter of thedeflectable region may vary across its length, for example, the diametermay decrease towards the middle of the deflectable region, and increasetowards the ends of the deflectable region. The deflectable region 3404may be any suitable length that provides sufficient flexibility fortracking through a curved cannula, for example, from about 0.02 inch toabout 0.15 inch, e.g., 0.085 inch. The overall length of the stylet 3400may be from about 7 inches to about 9 inches, e.g., 8.05 inches. Thedeflectable region 3404 may be located a certain length away from thedistalmost portion of the distal tip 3402, for example, about 0.05 inchto about 0.3 inch, such as 0.204 inch. The reduced dimension of thedeflectable region can may be used as a reference marker, e.g., duringfluoroscopic visualization. Accordingly, the length of the deflectableregion, the diameter of the deflectable region, and distance of thedeflectable region from the distal-most portion of the distal tip may bevaried to provide specific dimensional measurements or references. Whilethe deflectable region 3404 may be substantially straight, thedeflectable region may have one or more pre-formed curves. In somevariations, the deflectable region 3404 may be integrally formed withthe distal tip 3402 and/or the portion of the elongate body 3408 that isproximal to the deflectable region. Alternatively, the deflectableregion 3404 may be separately formed and attached to the distal tip 3402and the proximal portion of the elongate body 3408. The deflectableregion 3404 may be made of any of the materials previously described,for example, rigid or semi-rigid materials, such as stainless steel ornickel titanium alloy. The distal tip 3402 may be made of similarmaterials, and may have any geometry as described previously. Somevariations of a distal tip 3402 may be blunt, while other variations maybe sharpened. For example, as depicted in FIG. 34A, the distal tip 3402has a beveled conical shape, with a sharpened distalmost tip. Forexample, the distal tip 3402 may be a 3-sided beveled tip. The distaltip 3402 may have a length of about 0.150 inch to about 0.300 inch,e.g., 0.204 inch. On the proximal portion of the stylet, the proximalconnector 3406 may be able to interface and attach with variousconnectors of a tissue removal device, as described above. For example,the proximal connector 3406 may be a Luer-Lok™ type connector that mayconnect to a cannula with a complementary Luer-Lok™ type connector. Insome variations, the proximal connector 3406 may be made of a polymericmaterial, such as ABS or nylon.

FIG. 34B depicts one variation of a curved cannula 3430 comprising astraightened portion 3432 and a curved portion 3434 distal to thestraightened portion 3432. Optionally, a depth indicator, such as anadjustable flange, band, or silicone grommet, may be provided on theouter diameter of the curved cannula to reference the insertion depth ofthe cannula during use. The curved cannula 3430 may have a proximal hub3420 with a connector 3416, e.g., a female Luer Lok™ connector that maybe made of nylon. The proximal hub may further comprise an orientationindicator 3417 shown in FIGS. 34B and 34C. The orientation indicator3417 may have a shape that tapers to a rounded apex 3420, where theplane of the apex 3420 is aligned and/or co-planar with the plane of thecurved portion 3434. The shaft of the curved cannula may be made of 304stainless steel or Nitinol. The straightened portion 3432 may have alength L11, where L11 may be about 3 inches to about 6 inches, e.g.,4.36 inches. The curved portion 3434 may have a length L12, where L12may be about 2 inches to about 3 inches, e.g., 2.5 inches. Theproportion of the curved portion to the total length may be from about1:20 to about 1:2, for example, about 1:10, or 1:5, or 1:3. In somevariations, the entire length of the stylet may be curved. The cannula3430 may have any suitable diameter, e.g., 16 Gauge, or may have anouter diameter of about 0.068 inch, an inner diameter of about 0060inch. The total length of the cannula 3430 may be from about 6 inches toabout 8 inches, e.g., 7.21 inches. A similar straight cannula may have atotal length of about 7 inches. The curved portion 3434 may curve at anangle A5 with respect to the straightened portion 3432, where A5 may beabout 25° to about 50°, for example, about 35° to about 45°, or 40°.Alternatively or additionally, the radius of curvature of the curvedportion 3434 may be from about 3 inches to about 4.5 inches, e.g., 3.5inches. The curved cannula 3430 may have a diameter of about 0.050 inchto about 0.075 inch, e.g., 0.068 inch. Optionally, there may be one ormore markings 3435 that demarcate length increments. For example, themarkings 3435 may indicate 1.0 centimeter lengths. The markings 3435 mayhave varying thickness, e.g., alternating 0.2 inch and 0.06 inch. In thevariation of a curved cannula, the length L12 of the distal curvedportion 3434 is approximately 40% to 60% of the length L11 of thestraightened portion 3432, but in other variations, the lengthproportion of the curved portion to the straightened portion may vary. Astraight stylet may have one or more deformable regions as describedabove to accommodate the location, length, and angle of the curvedportion of a curved cannula. In some variations, the curved cannula 3430is made of 304 stainless steel, Nitinol, or any suitable material whichmay allow the curved portion 3434 to be straightened when a straightstylet is inserted therethrough.

In other variations, a stylet may be sized and shaped to match thecurvature of a corresponding cannula. For example, insertion of a styletwith curves corresponding to curves on a cannula may stiffen andmaintain the curvature of the cannula, which may facilitate therepositioning and/or manipulation of the cannula. In some variations,the location of a deformable region along a stylet, as well as thelength and flexibility of the deformable region may be determined inpart by the length and/or curvature of a cannula. FIGS. 30A to 30Bschematically illustrate another cannula-stylet assembly 3000 comprisinga curved cannula 3010 and a curved stylet 3020. The curved stylet 3020may comprise a straight proximal portion 3022 and a curved distalportion 3024, two of which are joined via a bend 3026. In someembodiments, the curved stylet 3020 may comprise a round or otherwiseblunt distal tip 3024 such that the insertion of the stylet 3020 may notdamage the interior of the cannula 3010 when the distal tip 3024 of thestylet 3020 passes through the curved cannula portion 3014. In someembodiments, a blunt distal tip may reduce the risk of tissue disruptionwhen the cannula-stylet assembly navigates to or about a target site butstill provide penetrating capability through soft tissues or bones(e.g., nucleus pulposus or cancellous bones). In some embodiments, thedistal tip of the curved stylet may be sharpened to enhance itspenetrating ability. The bend 3026 may be pre-shaped with a bend radiusand a bending range that are substantially the same as those of thecannula bend 3016. In this fashion, a curved cannula-stylet assembly3000 may be formed with the bend 3016 of the cannula 3010 and the bend3026 of the stylet 3020 substantially aligned with each other, asillustrated in FIG. 30B.

The curved stylet 3020 may be made from a flexible shape memory materialsuch that insertion of the curved distal portion 3024 into the curvedcannula 3010 may straighten the stylet 3020 but the stylet 3020 maysubstantially regain its curved configuration as the stylet passesthrough the cannula bend 3016. Non-limiting examples of suitable styletmaterials include shape memory metal alloys (e.g., nickel-titaniumalloy) and shape memory polymers. In some embodiments, a curved styletcomprises a fixed bending range and/or bend radius such that the curvedstylet may only be used with a curved cannula with substantially thesame bending range and/or bend radius. In other embodiments, the curvedstylet may be made from a flexible and/or malleable material such thatwhen the stylet passes through the curved portion of a curved cannula,the stylet may deform under compressive stress and assume a bendingconfiguration substantially the same as that of the curved cannula. Insuch embodiments, the curved stylet may be used in conjunction withcurved cannulas with a range of bending configurations (e.g., bendradius, bending range, etc.).

In some embodiments, the curved stylet may comprise a length (whenstraightened) of about 4 inches to about 12 inches or more, sometimesabout 5 inches to about 10 inches, and other times about 6 inches toabout 9 inches. In embodiments where the curved stylet comprises apre-shaped bend, the ratio between the length of the curved distalportion (when straightened) to the length of the straight proximalportion may be about 0.1 to about 0.9; sometimes about 0.2 to about 0.8;other times about 0.4 to 0.6. The outer diameter of the curved styletmay be about 0.04 inch to about 0.07 inch or more, sometimes about 0.05inch to about 0.06 inch, and other times about 0.05 inch to about 0.054inch. The bending range and/or bend radius of a curved stylet may beselected in part based upon the configuration of the curved cannula withwhich the curved stylet will be used. For example, FIG. 34C depicts onevariation of a curved stylet 3440 comprising a straightened portion 3442and a curved portion 3444 distal to the straightened portion 3442. Thestraightened portion 3442 may have a length L13, where L13 may be about4.5 inches to about 7 inches, e.g., 5.92 inches. The curved portion 3444may have a length L14, where L14 may be about 2.5 inches to about 4inches, e.g., 2.5 inches. The total length of the stylet 3440 may befrom about 7 inches to about 10 inches, e.g., 8.37 inches, and wheninserted into a cannula, the stylet tip may protrude from the distal endof the cannula. The curved stylet may have a diameter of about 0.030inch to about 0.060 inch, e.g., 0.039 inch or 0.054 inch. The curvedportion 3444 may curve at an angle A6 with respect to the straightenedportion 3442, where A6 may be about 25° to about 50°, for example, about35° to about 45°, or 40°. Alternatively or additionally, the radius ofcurvature of the curved portion 3444 may be from about 3 inches to about4.5 inches, e.g., 3.5 inches. The shaft of the curved stylet 3440 may bemade of stainless steel (304, 316, 17-4), cobalt chromium, titaniumalloy, Nitinol and may be covered with a fluoropolymer or coated withparylene, or materials with similar mechanical properties. Optionally,the proximal portion of the curved stylet 3440 may comprise a connector,such as a Luer Lock™ connector, and a curve orientation indicator, whichwill be described later on.

In some embodiments, once the curved cannula 3010 and the curved stylet3020 are coupled proximally, the distal end 3024 of the curved stylet3020 may be disposed at a fixed position distal to the distal end 3018of the curved cannula 3010. The distance between the distalmost end 3024of the curved stylet 3020 and the distalmost end 3018 of the curvedcannula 3010 may be in the range of about 0.02 inch to about 0.4 inch,sometimes about 0.04 inch to about 0.30 inch, and other times about 0.07inch to about 0.2 inch. In some embodiments, when the curved stylet 3020is proximally connected to the curved cannula 3010, the stylet 3020 maybe independently rotated inside the cannula 3010. In some embodiments,the curved cannula and the curved stylet may be coupled and/or locked bya proximal connector to prevent any relative motion. This may help toprevent any inadvertent misalignment during use of the assembly 3000.

Once the cannula has been positioned at the target tissue, andoptionally confirmed by imaging techniques, the stylet may be withdrawnfrom the cannula, and the tissue removal device may be advanced to thetarget tissue via the cannula. FIGS. 32A to 32C schematically illustratethe insertion of a cable-based tissue removal device 3150 into a curvedcannula 3110. The cable-based tissue removal device 3150 comprises ashaft 3152 and a distal tissue removal portion 3154. In someembodiments, the shaft 3152 of the tissue removal device 3150 maycomprise a pre-shaped curved configuration with a bend 3156, which maycomprise substantially the same bending characteristics (e.g., bendingrange, bend radius, etc.) as the bend 3116 of the curved cannula 3110.In such instances, the curved tissue removal device 3150 may be usedwith a curved cannula with a matching bend. In other embodiments, theshaft 3152 of the tissue removal device 3150 may be made from aflexible, semi-flexible material (e.g., shape memory alloys or shapememory polymer) or otherwise malleable material such that when thetissue removal device 3150 passes through the curved cannula 3110, theshaft 3152 may assume a curved configuration, forming a bend 3156substantially the same as the curved cannula 3110. In these embodiments,the flexible tissue removal device 3150 may be used in conjunction withcurved cannula with different bending characteristics (e.g., bendingrange, bend radius, etc.). Additionally or alternatively, such aflexible tissue removal device may also be used with a straight cannula.

A straight cannula and a straight stylet may be used in a variety ofspinal procedures and surgeries, including but not limited to discectomyand vertebroplasty, as well as diagnostic procedures. Prior to insertingthe tissue removal device into a patient, the device may be turned on toconfirm proper rotational and axial motion, as well as to ensure thatthe rotatable cable properly transitions between the retractedconfiguration and the extended configuration. The travel member shouldbe locked in the distal position. Once the patient is prepared for thesurgery as described above, the target disc level may be identifiedusing fluoroscopy or another appropriate imaging modality. Access to theaffected disc may be attained using either the straight cannula or thecurved cannula. To access the affected disc with the straight cannula,the sharpened stylet may be inserted into to the straight cannula, andthen fixedly attached together at their proximal hub, e.g. by a LuerLok™ connector. The straight cannula-sharpened stylet assembly may beadvanced into the affected disc under image guidance. For example, thecannula may be positioned parallel to disc endplates. The cannula tipmay be adjusted such that it rests within the disc nucleus, at theproximal location of the desired tissue removal zone. Optionally, asilicone marker or grommet may be provided on the straight and thecurved cannula to mark the cannula depth. Once the tip of the straightcannula is confirmed to be inside the disc, the sharpened stylet may beremoved as the cannula is held in place. To access the affected discwith the curved cannula, the sharpened stylet may be inserted into thecurved cannula, and then fixedly attached together at their proximalhub, e.g. by a Luer Lok™ connector. The curved cannula-sharpened styletassembly may be advanced into the affected disc under image guidance.Once the tip of the curved cannula is confirmed to be inside the disc,the orientation of the curve may also be adjusted according to awing-shaped orientation indicator at a proximal portion of the curvedcannula. Optionally, a silicone marker or grommet may be provided on thestraight and the curved cannula to mark the cannula depth. The sharpenedstylet may be removed, leaving the curved cannula in place. Then, thecurved stylet may be inserted into the curved cannula such that thestylet curve matches the cannula curve, i.e., the wing-shapedorientation indicator of the curved stylet matches the orientation ofthe wing-shaped orientation indicator of the curved cannula. Under imageguidance, the curved cannula-curved stylet assembly may be advanced tothe desired location. Once the curved cannula has been confirmed to bein the desired location, the curved stylet may be withdrawn as thecannula is held in place. As either the straight or curved cannula isadvanced through the disc region, the practitioner may use any suitableimaging modality to avoid advancing the cannula (or associated stylet)into or through the distal annular wall. After cannula penetration tothe vertebral disc, if the practitioner determines that an alternatecannula should be use to better access the targeted site, the exchangewire may be used to withdrawn the original cannula and to insert thealternate cannula, without creating a second access site.

Prior to inserting the tissue removal device into the cannula,approximately 0.5 cc of saline may be injected into the disc through thecannula. Under image guidance, the tissue removal device may be insertedthrough the cannula until the travel limiter has reached the proximalhub of the cannula. The travel limiter may be attached to the proximalhub of the cannula by rotating the handle in a clockwise direction.Releasing the locking ring and locking it in an intermediate positionmay allow the distal tip of the tissue removal device to be advanced upto 13.5 mm beyond the distal tip of the cannula. Securing the lockingring a distal position may allow the distal tip of the tissue removaldevice to be advanced up to 18.5 mm beyond the tip of the cannula. Thepractitioner may adjust the position of the locking ring as necessary.After each adjustment, the practitioner may confirm that within theconstraints imposed by the configuration of the travel limiter, thedistal end of the cannula is still in the disc nucleus. The practitionermay also confirm that the rotatable cable of the tissue removal assemblywill not contact the proximal or distal annulus as the device is axiallyadvanced and withdrawn along the axial length determined by the travellimiter. Using image guidance, the practitioner may advance the tip ofthe tissue removal device to the full plunge depth, and confirm that thetip is in a safe location. The tissue removal device may then be turnedon, and the configuration of the rotatable cable may be adjusted by aslider actuator on the handle, e.g., the rotatable cable may betransitioned from a retracted configuration to an extended or expandedconfiguration. In some variations, the sweep diameter of the rotatablecable in the extended configuration is about 7 mm. While the tissueremoval device is turned on, and securing the position of the cannula,the tissue removal device may be advanced and retracted to helpfacilitate tissue removal. The placement of the device in the course oftissue removal may be intermittently confirmed by fluoroscopy or anotherappropriate imaging modality. The tissue removal device may be useduntil sufficient tissue material has been removed, or the collector isfull. In some variations, a negative pressure source may be coupled tothe collector which may help expedite tissue removal. The markings onthe collector indicate the quantity of tissue removed. The tissueremoval device may be turned on and used continuously for about 0.5second to about 6.0 minutes, e.g., 2.0 minutes.

Once a sufficient quantity of tissue material has been removed, thetissue removal device may be turned off, and the rotatable cable may betransitioned to its retracted configuration. The locking ring of thetravel limiter may be secured in the distal position. The travel limitermay be disengaged from the proximal hub of the cannula, and then thetissue removal device may be withdrawn. The above steps may be repeateduntil the desired quantity of tissue has been removed. If additionaltreatment is required within the disc, the straight or curved stylet maybe reinserted into the cannula, and the cannula may be repositioned. Insome procedures, it may be desirable to limit the total run-time of thetissue removal device to about 6.0 minutes or less. The straight styletmay be inserted into the cannula and fixedly attached at the proximalhub. Then, the cannula-straight stylet assembly may be withdrawn fromthe access site. In some variations, the battery of the tissue removaldevice may be removed and disposed according to local regulations.

The cannula, stylet, and tissue removal devices described above may alsobe used to perform a discectomy. The devices may be used in a minimallyinvasive procedure, or an open surgery procedure. The cannula-styletassembly may be used to form a passageway or a working channel throughthe tissue about a target site in the spinal region. For example, toperform a discectomy procedure, the patient is prepped and draped in theusual sterile fashion and in a lateral decubitis or prone position.General, regional or local anesthesia is achieved. A straight styletwith a sharp distal tip may be inserted into the lumen of a straightcannula. The assembly may then be percutaneously inserted through aposterior or posterolateral entry point on the back of the patient. Thecannula-stylet assembly may be further inserted into the epidural spaceor into the paravertebral space, depending on the assembly's point ofentry. Alternatively, the assembly may be used to penetrate the discannulus directly from a point of entry further away from the midline ofthe patient's back. In some embodiments, the assembly may be introducedon the ipsilateral side from which the nerve impingement has beenidentified and at an angle of about 25 degrees to about 45 degrees tothe patient's back. In other procedures, a contralateral approach and/ora different angle may be used. In alternative embodiments, an anteriorprocedure through the abdominal cavity of the anterior neck region maybe performed.

The cannula-stylet assembly may be advanced together to a target tissuesite, as described above. During the insertion of the assembly, thestylet may be independently rotatable such that the operator may adjustthe orientation of the optional beveled edge of the stylet in order toform a passageway through the surrounding tissue, bones or otheranatomic structures. The insertion of the cannula-stylet assembly may beperformed under the guidance of external imaging and/or visualizationtechniques.

FIGS. 26A and 26B schematically illustrate one embodiment of a straightaccess to the spinal disc area by a straight cannula-stylet assembly2600. FIG. 26A is a side cut-away view of the access and FIG. 26B issuperior cut-away view of the access. Where the cannula 2610 and stylet2620 comprise a relatively stiff material (e.g., stainless steel), theassembly 2600 may provide increased tactile responsiveness, torquabilityand/or pushability when manipulated proximally over longer insertiondistances. In some embodiments, the assembly of a straight cannula 2610and a straight stylet 2620 may be inserted directly into the discannulus 2630. The sharp distal tip 2622 of the stylet may facilitateobtaining access to the herniated area 2640 by penetrating the discannulus 2630.

Once access to the herniated area is confirmed by fluoroscopy or othertypes imaging or visualization techniques, the stylet 2620 may beremoved, followed by the insertion of a tissue removal device. In someembodiments, before the tissue removal device is inserted, an endoscopemay be used to evaluate the target site access. Examples of endoscopicsystems that may be used with the cannula-stylet assembly are describedin U.S. application Ser. No. 11/362,431, U.S. application Ser. No.11/373,059, U.S. application Ser. No. 12/199,706, and U.S. Appl. No.61/106,914, which are hereby incorporated by reference in theirentirety. The endoscope may facilitate direct visualization andidentification of the relevant structures such as the disc, the nerve orother adjacent structures and the site(s) to tissue removal. Theendoscope may be inserted into the cannula subsequent to the removal ofthe stylet, or may be introduced through an additional lumen in thecannula. In other examples, a guidewire may be inserted into the cannulaand the cannula is removed to permit positioning of the endoscope usingthe guidewire.

Referring back to FIG. 26C, once the cannula placement at the targetsite has been confirmed, a tissue removal device 2650 having a distalhead 2651 (FIG. 26D) may be inserted into the cannula 2610 and advancedinto the nucleus 2640 of the disc 2641. The tissue removal device 2650may be a mechanical tissue removal device that may be motorized ormanually activated, including but not limited to burr, trephine, orcable-based tissue removal device as described previously. In otherexamples, the tissue removal device may be an energy-based device (e.g.laser, RF, high-intensity focused ultrasound) or a chemical-based (e.g.injection or infusion of a sclerosant or chemical ablation agent). Thetissue removal device may be used to remove disc material either bydissecting, aspirating, dissolving, or shrinking the nucleus. In onespecific example, a cable-based tissue removal device 2650 may beinserted into the cannula 2610 and advanced to the herniated area 2640.The distal portion of the tissue removal device 2650 may be radiopaqueto allow the device to advance under external imaging guidance. Thedevice 2650 may comprise a proximal connector that allows releasableattachment of the device 2650 to the cannula 2610. FIG. 26D is adetailed view of the tissue removal device 2650 that is proximallyattached to the cannula 2610 with the spiral cable 2654 in a deployedconfiguration. In some embodiments, once the device 2650 is proximallyattached to the cannula 2610, the port 2652, through which the cable2654 is proximally attached to the device 2650, is disposed distally tothe distal end 2612 of the cannula 2610. This ensures that thedeployment of the cable 2654 will not be interfered with by the cannula2610. In some embodiments, the tissue removal device 2650 may comprisean aspiration port 2656, which is configured to aspirate emulsified orpulverized nucleus fibrosus broken and removed by the spiral cable 2654.In some embodiments, once the device 2650 is attached to the cannula2610, the aspiration port 2656 may be at least partially covered by thecannula 2610 such that the port 2656 will not be clogged by largerpieces of disc material. In FIG. 26D, a tissue transport assembly 2658is depicted extending from aspiration port 2656.

In some embodiments, after the tissue removal device 2650 is proximallyattached to the cannula 2610, the device 2650 may be advanced furtherwithin the cannula 2610 in order to enlarge the tissue removal zone,which is defined by the motion of the deployed cable 2654. In someexamples, a travel limiter may be employed to limit the distal travel ofthe tissue removal device 2650 with respect to the distal end of thecannula 2610, as described previously. The maximum distal traveldistance of the tissue removal device may be less than about 2centimeter, sometimes less than about 1 centimeter, and other times lessthan about 0.5 centimeter. The travel limiter may also be used toprevent the tissue device from traveling too far and thereby, leavingthe herniated area. The advancement of the tissue removal device 2650within the cannula may be monitored under fluoroscopy or other types ofimaging guidance. The tissue removal device 2650 may be of any maximumtransverse axial dimension with the spiral cable 2654 retracted that issmaller than the inner diameter of the cannula 2610. In someembodiments, with the cable 2654 extended or deployed, the maximumradial displacement of the wire 2654 may be in the range of about 0.07inch to about 0.2 inch, sometimes in the range of about 0.09 inch toabout 0.2 inch, and other times in the range of about 0.1 inch to about0.15 inch.

Referring back to FIG. 26D, once the placement of the tissue removaldevice 2650 is confirmed, the cable 2654 may be deployed and actuated toemulsify or pulverize the tissue of the disc. The position of the device2650 may be adjusted (e.g., advanced and retracted) relative to thecannula 2610 during one session of actuation in order to enlarge thetissue removal zone distally. In other embodiments, the position of thedevice 2650 may be adjusted during the intervals between the actuationsessions of the device.

Fluoroscopy and/or CT scan may be used before, during and/or after theprocedure to assess the patient's anatomy, the position of theinstruments, the structural changes after tissue removal, and/or toverify the integrity of the disc. In some embodiments, a small amount ofradiopaque contrast may be injected into the disc space to enhancevisualization. Such injection may be performed by the tissue removaldevice through an infusion or irrigation channel, or through theaspiration port. In other embodiments, the cannula may comprise aninfusion or irrigation lumen to introduce the contrast agents. In someembodiments, the tissue removing procedure may be assessed by thequantity and/or color of the tissue removed through an opticallytransparent chamber, or collection chamber. Upon completion of theprocedure, the tissue removal device 2650 may be proximally withdrawn,followed by withdrawal of the cannula 2610.

A straight cannula and a straight stylet may also be used forvertebroplasty. In one specific example illustrated in FIGS. 28A to 28C,a straight cannula-stylet assembly 2800 may be percutaneously enteredinto tissue surrounding the spine until the sharp and optionally beveledstylet tip 2822 reaches the outer surface of the vertebral body 2830 ofinterest. The sharp stylet tip 2822 may be used to form a passageway orworking channel through the compact bone of the vertebral body 2830. Insome embodiments, the stylet 2820 may only be used to penetrate theouter surface of the vertebral body 2830. Another surgical instrument(e.g., a dilator or an obturator), subsequent to the removal of thestylet 2820, may be used to enlarge the penetration site to form thepassageway or working channel. The placement of the assembly 2800 toacquire access to the interior of the vertebral body may be guided byfluoroscopy, CT or ultrasound. Once the access to the fractured area2832 is confirmed, the stylet 2820 (or another tool used to form thepassageway) may be removed and a tissue removal device 2840, such as thecable-based tissue removal device 2840 depicted in FIG. 28C, may beinserted into the cannula 2810 to remove diseased bone tissue (e.g.,cancerous cells). In some embodiments, the cable-based tissue removaldevice 2840 may be used to form a cavity 2834, into which bone cement orother materials may be injected to stabilize the fracture caused byosteoporosis, tumors or severe trauma. In some embodiments, the tissueremoval device 2840 may comprise an infusion or aspiration channel,which may be used to collect diseased bone tissue for diagnosis orevaluation. Such an infusion or aspiration channel may also be used tocollect removed bone tissues during the tissue removing procedure.Devices and methods to use a cable-based tissue removal device invertebroplasty have been described in detail above and will not berepeated here for the sake of brevity.

Once the tissue removing procedure is completed, a fluoroscopy or CTscan may be performed to examine the vertebral body. In someembodiments, the tissue removal device may comprise a pressure sensor,which may be used to read the internal pressure in the vertebral body.Based on the pressure reading, the operator may be informed when thefractures are adequately filled and/or integrity of the vertebral bodyhas been regained. Upon completion of the procedure, the tissue removaldevice 2840 may be proximally withdrawn from the cannula 2810, followedby withdrawal of the cannula 2810.

While a vertebroplasty may be performed using a straight cannula, abendable flexible curved cannula may also be used. As described above, astraight or curved stylet may be used with a bendable flexible curvedcannula to position the cannula at the targeted tissue site. Asillustrated in FIGS. 33A to 33D, a straight cannula-stylet assembly 3300comprising a curved cannula 3310 straightened by a straight stylet 3310may first be percutaneously entered into spinal muscle to form apassageway through the outer surface of the vertebral body 3330. Theinitial straight assembly placement may be closer to the outer surfaceof the vertebral body compared to the initial placement of a straightcannula-stylet assembly in a straight access, where the distal tip ofthe stylet needs to reach the fractured area that is closer to thecentral vertebral body (as shown in FIG. 28B). As a result, the initialplacement of a curved assembly in vertebroplasty may involve a shorterand more direct insertion path.

Once access to the interior of the vertebral body 3330 is confirmed, thestraight stylet 3310 may be replaced with a curved stylet 3340. A curvedcannula-stylet assembly 3301 is formed with the cannula 3310 and thestylet 3330 proximally coupled to each other and with their curvedportions aligned. In some embodiments, the curved stylet 3340 maycomprise a blunt distal tip, which may sufficiently penetrate cancellousbone, thereby facilitating the movement of the curved cannula-styletassembly 3301 inside the vertebral body 3330. In other embodiments, thedistal tip of the curved stylet 3340 may be sharpened in order toenhance its piercing ability. A curved cannula-stylet assembly 3301 maybe used to access central vertebral body area that is difficult to reachby a straight cannula-stylet assembly. Once access to a target site isconfirmed, a tissue removal device (e.g., a cable-based tissue removaldevice 3150 as depicted in FIG. 33D) may be inserted, subsequent to theproximal withdrawn of the curved stylet 3330. A tissue removal devicemay be used to form cavities inside the vertebral body 3330, to removediseased tissues (e.g., cancerous cells), and/or to inject bone cementinto fractured area to reinforce spine support. The tissue removaldevice may also be used to collect bone tissues through an aspirationand/or an infusion channel for diagnosis. A tissue removal device 3350extended from the distal end of a curved cannula provides a greaterreaching zone for tissue removal. For example, the proximal insertion ofthe assembly 3301 may advance the tissue removal device 3350 towards thecentral area of the vertebral body, thereby providing greater distalreaching distance. Further, the orientation of the cannula bend 3116 maybe adjusted with respect to the longitudinal axis 3313 of the straightcannula shaft 3311, thereby providing the tissue removal device 3350enhanced angular access, compared to a straight access. As a result,larger cavities may be formed by the tissue removal device 3350 used inconjunction with a curved cannula 3310, compared with the same deviceused with a straight cannula. In some embodiments, if multiple cavityformation is desired, a stylet (either straight or curved) may bereinserted into the curved cannula, subsequent to the withdrawn of thetissue removal device, in order to gain access to an adjacent targetarea. In some embodiments where penetration of compact bone may beinvolved, a straight stylet may be first reinserted and a straightcannula-stylet assembly is used to form a passage way or a workingchannel to another target site. The straight stylet may then be replacedwith a curved stylet to obtain more accurate access to the target site.In other embodiments where the second target site may be accessiblewithout compact bone penetration, a curved stylet may be reinserteddirectly following the withdrawn of the tissue removal device. Onceaccess to the second target site is confirmed, the tissue removal devicemay be reinserted following the proximal removal of the curved stylet toperform bone tissue removal. Such procedures may be repeated untiltreatments at multiple target sites are completed. As noted above, uponthe completion of bone tissue removal and/or bone cement injection, afluoroscopy or a CT scan may be performed to examine the bone integrity.In some embodiments, the examination may be performed by examining thequantity, color and/or texture of removed bone tissue collected in theproximal collecting chamber. Upon the completion of the vertebroplasty,a straight stylet may be inserted into the curved cannula, subsequent tothe removal of the tissue removal device and the cannula and stylet maythen be proximally withdrawn together.

FIGS. 31A to 31C schematically illustrate a curved access to a herniateddisc 3141 by a cannula-stylet assembly comprising a curved cannula 3110,a straight stylet 3120 and/or a curved stylet 3130. Once the patient isprepared for the discectomy procedure, a straight cannula-styletassembly 3100 may be formed by inserting a straight stylet 3120 into acurved cannula 3110. The assembly 3100 may then be insertedpercutaneously through a posterior or a posterolateral entry point onthe back of the patient. As shown in FIG. 31A, the insertion of thestraight stylet 3120 straightens the curved cannula 3110 and rendersassembly 3100 in a straight configuration. Because the straight stylet3120 is made from a relatively rigid material (e.g., stainless steel),the assembly 3100 may provide enhanced user responsiveness andmaneuverability while penetrating the patient's skin, muscle, and bodytissues. The straight stylet 3120 with sharpened distal tip may be usedto form a passageway or a working channel through the disc annulus. Asnoted above, a discectomy procedure using a straight access (as shown inFIGS. 26A and 26B) may involve inserting an assembly of a straightcannula and a straight stylet over a longer path in the patient's backin order to achieve sufficient access to the herniated area forexcision. By contrast, in a discectomy using a curved access, a shorterand/or more direct insertion path may be taken to the target site. Forexample, as illustrated in FIG. 31A, the straight cannula-styletassembly 3100 may be inserted from an entry point closer to the midline3144 of the patient's back until the distal tip of the stylet 3120penetrates the disc annuals 3130 and reaches an area in close proximityto the target herniated area. As will be discussed in greater detailbelow, a curved cannula-stylet assembly will then be used to reach thetarget herniated area for treatment. Because the initial straightcannula-stylet placement is closer to the outer surface of the vertebraldisc, the insertion path of the cannula-stylet assembly in a curvedaccess may be shorter and more direct, compared to the initial placementof the assembly in a straight access.

Once the straight cannula-stylet assembly 3100 reaches the interior ofthe vertebral disc, the straight stylet 3020 may be proximally removed,allowing the curved cannula 3110 to substantially regain its curvedconfiguration, as shown in FIG. 31B. In some embodiments, beforeproximally removing the straight stylet 3120, the operator may adjustthe orientation of the bend 3116 to ensure that the distal portion 3112cannula will bend towards the herniated area 3140 when the straightstylet 3120 is withdrawn. Following the removal of the straight stylet3120, a curved stylet 3130 may be inserted into the cannula 3110,forming a curved cannula-stylet assembly 3101, as illustrated in FIG.31C. The curved stylet 3130 may be radiopaque to permit the insertionunder external imaging guidance. In some embodiments, a stylet with amatching pre-shaped bend with the cannula may be used. In suchinstances, the operator may adjust the orientation of the stylet bendduring the insertion to ensure that the bend of the stylet and that ofthe cannula are aligned with each other. In other embodiments, a styletmade of flexible material may be used such that when the stylet passesthrough the curved portion of the curved cannula, it may assume a curvedconfiguration substantially the same as the cannula.

The curved stylet 3130 may be releasably coupled with the curved cannulaproximally. In some embodiments, once the stylet 3130 is attached to thecannula 3110, both the longitudinal and the axial movements of thestylet 3130 relative to the cannula 3110 are locked such that an alignedcannula-stylet assembly 3101 may be advanced together to the target sitefor excision. In some embodiments, the curved stylet 3130 may comprise ablunt distal tip that still may penetrate the nucleus, thereby acquiringaccess to the herniated area. The blunt tip may reduce the risk oftissue disruption or damage, especially in the situations where thecurved assembly 3101 is misplaced during its insertion. When the curvedcannula-stylet assembly 3101 is proximally inserted, its curved distalend may be advanced laterally towards the central portion of theherniated disc 3141. Such intra-discal area access may be challenging ifa straight access is used. Further, during the insertion of the curvedassembly 3130, the operator may adjust the orientation of the bend tosteer the distal tip of the assembly 3101 in the intra-discal area,thereby acquiring access to some target site that is difficult to reachby a straight access.

Once the access to the target site for excision by the curvedcannula-stylet assembly 3101 is confirmed by fluoroscopy or otherimaging or visualization techniques (e.g., endoscope or radiographicmarker), the curved stylet 3130 may be proximally withdrawn, followed bythe insertion of a tissue removal device. FIG. 31D schematicallyillustrates a cable-based tissue removal device 3150 extended distallyfrom a curved cannula 3110.

The tissue removal device 3150 may be proximally attached to the curvedcannula 3110 through complementary proximal connectors. In someembodiments, once attached, the distal tissue removal portion 3154 isexposed distally with respect to the distal end 3112 of the curvedcannula 3110 such that the deployment of the spiral wire 3156 will notbe blocked or otherwise interfered with by the distal end 3112 of thecurved cannula 3110. In some embodiments, the tissue removal device 3150may be further advanced distally inside the cannula 3110 after the twoare proximally attached and the maximum travel distance of the tissueremoval device 3150 may be limited by a travel limiter. As discussedabove, the distal travel of the tissue removal device 3150 is controlledsuch that the aspiration port 3160 may be at least partially covered bythe curved cannula 3110 during the insertion of the tissue removaldevice 3150 to prevent the clogging of the aspiration channel.

Where the placement of the tissue removal device 3150 is confirmed andevaluated, the device 3150 may be actuated to perform disc tissueremoval. A tissue removal device used in association with a curvedcannula may increase the region or amount of tissue removed, compared tothe same tissue removal device used with a straight cannula. Forexample, as illustrated in FIG. 26C, the tissue removing range 2655 ofthe tissue removal device 2650 extended from a straight cannula 2610 issubstantially limited by the pivoting range of the straight cannulashaft 2611. Any small annular movement of the tissue removal device 2650may involve substantial lateral displacement of the straight proximalportion of the cannula 2610, which is limited by the body tissues alongthe insertion path of the cannula 2610. As a result, the tissue removalzone 2655 of a straight access is limited by the range that can bereached by the rotation of the extended cable 2654 with respect to thelongitudinal axis 2653 of the tissue removal device 2650. By contrast,during a curved access as illustrated in FIG. 31D, rotating the shaft3111 of the curved cannula 3110 and adjusting the orientation of thecannula bend 3116 allows the tissue removal device 3150 to moveangularly with respect to the longitudinal axis 3113 of the cannulashaft 3111, thereby significantly increasing the range that can bereached by the extended cable 3154. Further, the tissue removal zone ofthe tissue removal device 3150 may be further increased by distaldisplacement of the tissue removal device 3150 with respect to thedistal end of the curved cannula 3110. In some embodiments, the verticaldisplacement of the extended cable 3154 with respect to the longitudinalaxis 3151 of the tissue removal device 3150 may be adjusted to furtherincrease the tissue removal zone. If the movements described above arecombined, an even greater tissue removal zone may be achieved.

After confirming a desired degree of tissue removal using imagingtechniques, the tissue removal device may be removed. To treat a secondtissue site, a curved or a straight stylet may be reintroduced to thecannula. In some embodiments, access to another herniated area mayrequire removal of the curved cannula from the disc annulus (e.g., thetarget site is located on the other side of the disc or the target siteis in another vertebral disc). In this scenario, a straight stylet maybe first inserted into the cannula to replace the tissue removal device,forming a straight cannula-stylet assembly. The operator may then removethe assembly from the disc annulus and, if appropriate, re-insert theassembly into the disc annulus from another entry point, therebyacquiring access to a second target site. After the annulus ispenetrated, the straight stylet may be replaced with a curved stylet anda curved cannula-stylet assembly may be formed to be placed at thesecond target site within the disc.

Once the placement of the cannula is confirmed at an additional tissuesite, the stylet may be proximally withdrawn and a tissue removal devicemay be reintroduced and the tissue removal procedures as described abovemay be repeated. Upon completion of the treatment at the additionaltarget sites, another fluoroscopy or CT scan may be performed to examinethe outcome and/or to examine whether any other intra-discal area needsadditional tissue removal. Once all herniated areas are treated, thetissue removal device may be proximally removed. In some embodiments, astraight stylet may be first inserted into the curved cannula, forming astraight cannula-stylet assembly. The assembly may then be proximallyremoved from the patient's back.

Use of curved cannula-stylet assemblies in conjunction with tissueremoval devices may provide precise access and tissue removal at one ormore target sites. Where access to a target site affected by tumors isinvolved, the curved access described herein may be desirable especiallywhen the areas surrounding the target site are highly compromised by thetumor. Precise removal of diseased bone tissues while preserving healthyones may result in fewer complications, such as bone cement leakageand/or cancerous cells spreading.

While a mechanically-operated cable-based tissue removal device used inconjunction with cannula-stylet assemblies in spinal procedures (e.g.,discectomy and vertebroplasty) is described in detail herein, it shouldbe understood that other types of mechanical tissue removal devices(e.g., burrs, trephines, etc.) or energy-based tissue removal devicesmay be used, and are contemplated for use in either a straight access ora curved access to a spinal area.

While certain variations of impellers have been described as being usedwith certain variations of rotatable cable shafts, tubular members, etc.it should be understood that the variations of impellers may be usedwith other variations of rotatable cable shafts, tubular members, etc.Additionally, different variations of rotatable cable shafts may also beused with different cable configurations and drive shafts. Multiplevariations of the above-described components may be combined andassembled as appropriate for certain procedures. Examples of systems andkits that may be used for performing a minimally invasive discectomythat may comprise the various cannulas, stylets, tissue removal devicesare described herein. Similar systems and kits may generally be used forcutting, grinding, and aspirating intervertebral disc material duringprocedures in the lumbar spine. One variation of a kit for minimallyinvasive discectomy may comprise a straight cannula, a straight stylet,and a tissue removal device. Another variation of a kit may furthercomprise a sharpened stylet, a curved cannula, a second straight stylet,a curved stylet, an exchange wire, and a tissue removal device. Thecannula(s) may be 16 gauge, and the stylets may be appropriately sizedand shaped so that they may be advanced through the cannula(s). Theexchange wire may have a diameter of about 0.054 inch and be about 17inches long, or any length that is appropriate for minimally invasivelyaccessing a region of tissue within a vertebral disc. The exchange wiremay be made of 304 stainless steel or other comparable material. Thetissue removal device may comprise a handle, a collector coupled to thedistal portion of the handle, a travel limiter attached distally to thecollector, an outer tube that provides a conduit between the collectionchamber and a distal tissue removal assembly. The tissue removalassembly may have a rotatable cable that has a retracted configurationand an extended configuration. The locking ring of a travel limiter mayhave a distal position, an intermediate position, and a proximalposition along the axis of the outer tube, and may be configured to lockin one or more positions. The outer tube may have a length that providesa 7 inch working length. The individual devices and components of a kitfor minimally invasive discectomy may be provided in a sterilizedpackage. In some variations, the devices may not be re-sterilized afteruse, while in other variations, certain devices, such as the cannulas,stylets, may be re-sterilized for use in another patient.

It is to be understood that this invention is not limited to particularexemplary embodiments described, as such may, of course, vary. It isalso to be understood that the terminology used herein is for thepurpose of describing particular embodiments only, and is not intendedto be limiting, since the scope of the present invention will be limitedonly by the appended claims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassedwithin the invention. The upper and lower limits of these smaller rangesmay independently be included or excluded in the range, and each rangewhere either, neither or both limits are included in the smaller rangesis also encompassed within the invention, subject to any specificallyexcluded limit in the stated range. Where the stated range includes oneor both of the limits, ranges excluding either or both of those includedlimits are also included in the invention.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, some potential andpreferred methods and materials are now described. All publicationsmentioned herein are incorporated herein by reference to disclose anddescribe the methods and/or materials in connection with which thepublications are cited. It is understood that the present disclosuresupersedes any disclosure of an incorporated publication to the extentthere is a contradiction.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “ablade” includes a plurality of such blades and reference to “the energysource” includes reference to one or more sources of energy andequivalents thereof known to those skilled in the art, and so forth.

The publications discussed herein are provided solely for theirdisclosure. Nothing herein is to be construed as an admission that thepresent invention is not entitled to antedate such publication by virtueof prior invention. Further, the dates of publication provided, if any,may be different from the actual publication dates which may need to beindependently confirmed.

What is claimed as new and desired to be protected is:
 1. A tissue removal system, comprising: a handheld housing; an outer shaft comprising a distal portion and a proximal portion, the proximal portion coupled to the handheld housing; a distal sheath coupled to the distal portion of the outer shaft; a motor; an inner shaft including a lumen having a distal opening, the inner shaft coupled to the motor, the inner shaft being located partially within the outer shaft and partially within the distal sheath, the distal sheath including a cylindrical portion extending circumferentially about the inner shaft; a tip portion having a proximal end, a side opening, and a lumen extending therebetween, the tip portion coupled to a distal portion of the inner shaft; and an elongate member slidably coupled to the lumen of the inner shaft and the lumen of the tip portion, the elongate member configured to slidably extend through the tip portion, the elongate member having a retracted configuration and an extended configuration, wherein the distal sheath comprises at least one element that engages the tip portion to couple the tip portion to the distal sheath.
 2. The system of claim 1, wherein the at least one element comprises at least one protrusion extending from an inner surface of the distal sheath.
 3. The system of claim 2, wherein the at least one protrusion comprises a plurality of protrusions.
 4. The system of claim 3, wherein the at least one protrusion comprises four protrusions.
 5. The system of claim 1, wherein the coupling between the tip portion and the distal sheath defines at least one aspiration port therebetween.
 6. The system of claim 5, wherein the coupling between the tip portion and the distal sheath defines a plurality of aspiration ports therebetween.
 7. The system of claim 1, wherein the distal sheath comprises a wall portion having at least one aperture therethrough.
 8. The system of claim 7, wherein the wall portion has a plurality of apertures therethrough.
 9. The system of claim 8, wherein the wall portion has two apertures therethrough.
 10. The system of claim 1, further comprising a stop member coupled to the tip portion.
 11. The system of claim 1, further comprising a tissue transport assembly.
 12. The system of claim 11, wherein the tissue transport assembly comprises the inner shaft and a helical member coupled to the inner shaft.
 13. The system of claim 11, wherein the tissue transport assembly comprises the inner shaft and a helical member integral with the inner shaft.
 14. A tissue removal system, comprising: a handheld housing; an outer shaft comprising a distal portion and a proximal portion coupled to the handheld housing; a distal sheath coupled to the distal portion of the outer shaft; a motor; an inner shaft including a lumen having a distal opening, the inner shaft coupled to the motor, the inner shaft being located partially within the outer shaft and partially within the distal sheath, the distal sheath including a cylindrical portion extending circumferentially about the inner shaft; a tip portion having a proximal end a side openg and a lumen extending therebetween the tip portion coupled to a distal portion of the inner shaft; a stop member coupled to the tip portion; and an elongate member slidably coupled to the lumen of the inner shaft and the lumen of the tip portion, the elongate member configured to slidably extend through the tip portion, the elongate member having a retracted configuration and an extended configuration.
 15. The system of claim 14, wherein the stop member surrounds an outer surface of the tip portion.
 16. The system of claim 15, wherein the stop member is annular.
 17. The system of claim 16, wherein the stop member is beveled.
 18. The system of claim 14, further comprising a tissue transport assembly.
 19. The system of claim 18, wherein the tissue transport assembly comprises the inner shaft and a helical member coupled to the inner shaft.
 20. The system of claim 18, wherein the tissue transport assembly comprises the inner shaft and a helical member integral with the inner shaft.
 21. A tissue removal system, comprising: a handheld housing; an outer shaft comprising a distal portion and a proximal portion coupled to the handheld housing; a distal sheath coupled to the distal portion of the outer shaft; a motor; an inner shaft including a lumen having a distal opening, the inner shaft coupled to the motor, the inner shaft being located partially within the outer shaft and partially within the distal sheath, the distal sheath including a cylindrical portion extending circumferentially about the inner shaft; a tip portion having a proximal end, a side opening, and a lumen extending therebetween, the tip portion coupled to a distal portion of the inner shaft, the tip portion including a stop member; an elongate member slidably coupled to the lumen of the inner shaft and the lumen of the tip portion, the elongate member configured to slidably extend through the side opening of the tip portion, the elongate member having a retracted configuration and an extended configuration, wherein the stop member of the tip portion is configured to limit proximal movement by the inner shaft. 